How to Reference Gridview child controls

M

Mike

Hello,

I have a gridview that I want to basically convert to behavior like Excel
autofilter. I have created a dropdown list and put it into the header of the
gridview, but I can't seem to reference it correctly. I have been trolling
through the net and ms references for hours but I can't get it straight.

Here is the html code:

<%@ Page Language="VB" AutoEventWireup="false"
CodeFile="datagridtest4.aspx.vb" Inherits="datagridtest4" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>

</div>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataSourceID="AccessDataSource1">
<Columns>
<asp:TemplateField HeaderText="Vendor" SortExpression="Vendor">
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text='<%#
Bind("Vendor") %>'></asp:TextBox>
</EditItemTemplate>
<HeaderTemplate>
<asp:DropDownList ID="DropDownList1" runat="server"
AutoPostBack="True"
DataSourceID="AccessDataSource1"
DataTextField="Vendor"
DataValueField="VendorID"

onselectedindexchanged="DropDownList1_SelectedIndexChanged">
</asp:DropDownList>
<asp:AccessDataSource ID="AccessDataSource1"
runat="server"
DataFile="~/App_Data/courses.mdb"
SelectCommand="SELECT * FROM [tblVendors] ORDER BY
[Vendor]">
</asp:AccessDataSource>
</HeaderTemplate>
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%#
Bind("Vendor") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="BasicCourseName"
HeaderText="BasicCourseName"
SortExpression="BasicCourseName" />
</Columns>
</asp:GridView>
<asp:AccessDataSource ID="AccessDataSource1" runat="server"
DataFile="~/App_Data/courses.mdb"
SelectCommand="SELECT * FROM
[qryCoursesByVendors]"></asp:AccessDataSource>
</form>
</body>
</html>


I don't know where to attach the code behind the form; on the dropdown list
changed event, or the page load event, or...? I am sorry if this is stupid,
but I can't seem to get it. Here is what I have in the code behind the form:

Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object,
ByVal e As System.EventArgs)

Dim ddlVendor As DropDownList
ddlVendor = Me.GridView1.FindControl("DropDownList1")
AccessDataSource1.FilterExpression = "VendorID = " &
ddlVendor.SelectedItem.Text

End Sub

I have also experimented with:
ddlVendor = CType(GridView1.TemplateControl.FindControl("DropDownList1"),
DropDownList)

I get the following error message:

Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information about
the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set
to an instance of an object.

Source Error:


Line 36: Dim ddlVendor As DropDownList
Line 37: ddlVendor = Me.GridView1.FindControl("DropDownList1")
Line 38: AccessDataSource1.FilterExpression = "VendorID = " &
ddlVendor.SelectedItem.Text
Line 39: End If


Is there any way to implement this type of thing, or is this a nightmare? I
am a beginning programmer, and I've already spent many days making only
incremental advances.

thanks in advance for your help and support.

mike
 
M

Mike

Anyone? I'm still stuck! Thanks!

Mike said:
Hello,

I have a gridview that I want to basically convert to behavior like Excel
autofilter. I have created a dropdown list and put it into the header of the
gridview, but I can't seem to reference it correctly. I have been trolling
through the net and ms references for hours but I can't get it straight.

Here is the html code:

<%@ Page Language="VB" AutoEventWireup="false"
CodeFile="datagridtest4.aspx.vb" Inherits="datagridtest4" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>

</div>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataSourceID="AccessDataSource1">
<Columns>
<asp:TemplateField HeaderText="Vendor" SortExpression="Vendor">
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text='<%#
Bind("Vendor") %>'></asp:TextBox>
</EditItemTemplate>
<HeaderTemplate>
<asp:DropDownList ID="DropDownList1" runat="server"
AutoPostBack="True"
DataSourceID="AccessDataSource1"
DataTextField="Vendor"
DataValueField="VendorID"

onselectedindexchanged="DropDownList1_SelectedIndexChanged">
</asp:DropDownList>
<asp:AccessDataSource ID="AccessDataSource1"
runat="server"
DataFile="~/App_Data/courses.mdb"
SelectCommand="SELECT * FROM [tblVendors] ORDER BY
[Vendor]">
</asp:AccessDataSource>
</HeaderTemplate>
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%#
Bind("Vendor") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="BasicCourseName"
HeaderText="BasicCourseName"
SortExpression="BasicCourseName" />
</Columns>
</asp:GridView>
<asp:AccessDataSource ID="AccessDataSource1" runat="server"
DataFile="~/App_Data/courses.mdb"
SelectCommand="SELECT * FROM
[qryCoursesByVendors]"></asp:AccessDataSource>
</form>
</body>
</html>


I don't know where to attach the code behind the form; on the dropdown list
changed event, or the page load event, or...? I am sorry if this is stupid,
but I can't seem to get it. Here is what I have in the code behind the form:

Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object,
ByVal e As System.EventArgs)

Dim ddlVendor As DropDownList
ddlVendor = Me.GridView1.FindControl("DropDownList1")
AccessDataSource1.FilterExpression = "VendorID = " &
ddlVendor.SelectedItem.Text

End Sub

I have also experimented with:
ddlVendor = CType(GridView1.TemplateControl.FindControl("DropDownList1"),
DropDownList)

I get the following error message:

Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information about
the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set
to an instance of an object.

Source Error:


Line 36: Dim ddlVendor As DropDownList
Line 37: ddlVendor = Me.GridView1.FindControl("DropDownList1")
Line 38: AccessDataSource1.FilterExpression = "VendorID = " &
ddlVendor.SelectedItem.Text
Line 39: End If


Is there any way to implement this type of thing, or is this a nightmare? I
am a beginning programmer, and I've already spent many days making only
incremental advances.

thanks in advance for your help and support.

mike
Click to expand...
 
M

Mike

A little more update, I've also tried:

Dim ddlVendorFilter As DropDownList =
CType(gvCourses.FindControl("ddlVendor"), DropDownList)

MsgBox("ddlVendor Selected Value is" &
ddlVendorFilter.SelectedValue) 'Returns error

Mike said:
Hello,

I have a gridview that I want to basically convert to behavior like Excel
autofilter. I have created a dropdown list and put it into the header of the
gridview, but I can't seem to reference it correctly. I have been trolling
through the net and ms references for hours but I can't get it straight.

Here is the html code:

<%@ Page Language="VB" AutoEventWireup="false"
CodeFile="datagridtest4.aspx.vb" Inherits="datagridtest4" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>

</div>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataSourceID="AccessDataSource1">
<Columns>
<asp:TemplateField HeaderText="Vendor" SortExpression="Vendor">
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text='<%#
Bind("Vendor") %>'></asp:TextBox>
</EditItemTemplate>
<HeaderTemplate>
<asp:DropDownList ID="DropDownList1" runat="server"
AutoPostBack="True"
DataSourceID="AccessDataSource1"
DataTextField="Vendor"
DataValueField="VendorID"

onselectedindexchanged="DropDownList1_SelectedIndexChanged">
</asp:DropDownList>
<asp:AccessDataSource ID="AccessDataSource1"
runat="server"
DataFile="~/App_Data/courses.mdb"
SelectCommand="SELECT * FROM [tblVendors] ORDER BY
[Vendor]">
</asp:AccessDataSource>
</HeaderTemplate>
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%#
Bind("Vendor") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="BasicCourseName"
HeaderText="BasicCourseName"
SortExpression="BasicCourseName" />
</Columns>
</asp:GridView>
<asp:AccessDataSource ID="AccessDataSource1" runat="server"
DataFile="~/App_Data/courses.mdb"
SelectCommand="SELECT * FROM
[qryCoursesByVendors]"></asp:AccessDataSource>
</form>
</body>
</html>


I don't know where to attach the code behind the form; on the dropdown list
changed event, or the page load event, or...? I am sorry if this is stupid,
but I can't seem to get it. Here is what I have in the code behind the form:

Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object,
ByVal e As System.EventArgs)

Dim ddlVendor As DropDownList
ddlVendor = Me.GridView1.FindControl("DropDownList1")
AccessDataSource1.FilterExpression = "VendorID = " &
ddlVendor.SelectedItem.Text

End Sub

I have also experimented with:
ddlVendor = CType(GridView1.TemplateControl.FindControl("DropDownList1"),
DropDownList)

I get the following error message:

Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information about
the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set
to an instance of an object.

Source Error:


Line 36: Dim ddlVendor As DropDownList
Line 37: ddlVendor = Me.GridView1.FindControl("DropDownList1")
Line 38: AccessDataSource1.FilterExpression = "VendorID = " &
ddlVendor.SelectedItem.Text
Line 39: End If


Is there any way to implement this type of thing, or is this a nightmare? I
am a beginning programmer, and I've already spent many days making only
incremental advances.

thanks in advance for your help and support.

mike
Click to expand...
 
M

Mike

OK OK for what it's worth, here is the result of my stupid 25 hours of
digging...sheesh!

This does not throw an error:

Dim ddlVendorFilter As DropDownList =
gvCourses.HeaderRow.FindControl("ddlVendor")

I have not tried including it in a Ctype expression, and I'm not sure it's
necessary...

The key is including the HeaderRow in the code, because the control is in
the headerRow...I guess this is "duh!" for many of you, but perhaps it may
help a fool like me save several days of frustration...good luck!



Mike said:
A little more update, I've also tried:

Dim ddlVendorFilter As DropDownList =
CType(gvCourses.FindControl("ddlVendor"), DropDownList)

MsgBox("ddlVendor Selected Value is" &
ddlVendorFilter.SelectedValue) 'Returns error

Mike said:
Hello,

I have a gridview that I want to basically convert to behavior like Excel
autofilter. I have created a dropdown list and put it into the header of the
gridview, but I can't seem to reference it correctly. I have been trolling
through the net and ms references for hours but I can't get it straight.

Here is the html code:

<%@ Page Language="VB" AutoEventWireup="false"
CodeFile="datagridtest4.aspx.vb" Inherits="datagridtest4" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>

</div>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataSourceID="AccessDataSource1">
<Columns>
<asp:TemplateField HeaderText="Vendor" SortExpression="Vendor">
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text='<%#
Bind("Vendor") %>'></asp:TextBox>
</EditItemTemplate>
<HeaderTemplate>
<asp:DropDownList ID="DropDownList1" runat="server"
AutoPostBack="True"
DataSourceID="AccessDataSource1"
DataTextField="Vendor"
DataValueField="VendorID"

onselectedindexchanged="DropDownList1_SelectedIndexChanged">
</asp:DropDownList>
<asp:AccessDataSource ID="AccessDataSource1"
runat="server"
DataFile="~/App_Data/courses.mdb"
SelectCommand="SELECT * FROM [tblVendors] ORDER BY
[Vendor]">
</asp:AccessDataSource>
</HeaderTemplate>
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%#
Bind("Vendor") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="BasicCourseName"
HeaderText="BasicCourseName"
SortExpression="BasicCourseName" />
</Columns>
</asp:GridView>
<asp:AccessDataSource ID="AccessDataSource1" runat="server"
DataFile="~/App_Data/courses.mdb"
SelectCommand="SELECT * FROM
[qryCoursesByVendors]"></asp:AccessDataSource>
</form>
</body>
</html>


I don't know where to attach the code behind the form; on the dropdown list
changed event, or the page load event, or...? I am sorry if this is stupid,
but I can't seem to get it. Here is what I have in the code behind the form:

Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object,
ByVal e As System.EventArgs)

Dim ddlVendor As DropDownList
ddlVendor = Me.GridView1.FindControl("DropDownList1")
AccessDataSource1.FilterExpression = "VendorID = " &
ddlVendor.SelectedItem.Text

End Sub

I have also experimented with:
ddlVendor = CType(GridView1.TemplateControl.FindControl("DropDownList1"),
DropDownList)

I get the following error message:

Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information about
the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set
to an instance of an object.

Source Error:


Line 36: Dim ddlVendor As DropDownList
Line 37: ddlVendor = Me.GridView1.FindControl("DropDownList1")
Line 38: AccessDataSource1.FilterExpression = "VendorID = " &
ddlVendor.SelectedItem.Text
Line 39: End If


Is there any way to implement this type of thing, or is this a nightmare? I
am a beginning programmer, and I've already spent many days making only
incremental advances.

thanks in advance for your help and support.

mike
Click to expand...
Click to expand...
 
S

sskandekar

OK OK for what it's worth, here is the result of my stupid 25 hours of
digging...sheesh!

This does not throw an error:

Dim ddlVendorFilter As DropDownList =
gvCourses.HeaderRow.FindControl("ddlVendor")

I have not tried including it in a Ctype expression, and I'm not sure it's
necessary...

The key is including the HeaderRow in the code, because the control is in
the headerRow...I guess this is "duh!" for many of you, but perhaps it may
help a fool like me save several days of frustration...good luck!

Mike said:
A little more update, I've also tried:
Click to expand...
Dim ddlVendorFilter As DropDownList =
CType(gvCourses.FindControl("ddlVendor"), DropDownList)
Click to expand...
MsgBox("ddlVendor Selected Value is" &
ddlVendorFilter.SelectedValue) 'Returns error
Click to expand...
Hello,
I have a gridview that I want to basically convert to behavior like Excel
autofilter. I have created a dropdown list and put it into the header of the
gridview, but I can't seem to reference it correctly. I have been trolling
through the net and ms references for hours but I can't get it straight.
Here is the html code:
<%@ Page Language="VB" AutoEventWireup="false"
CodeFile="datagridtest4.aspx.vb" Inherits="datagridtest4" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
</div>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataSourceID="AccessDataSource1">
<Columns>
<asp:TemplateField HeaderText="Vendor" SortExpression="Vendor">
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text='<%#
Bind("Vendor") %>'></asp:TextBox>
</EditItemTemplate>
<HeaderTemplate>
<asp:DropDownList ID="DropDownList1" runat="server"
AutoPostBack="True"
DataSourceID="AccessDataSource1"
DataTextField="Vendor"
DataValueField="VendorID"
onselectedindexchanged="DropDownList1_SelectedIndexChanged">
</asp:DropDownList>
<asp:AccessDataSource ID="AccessDataSource1"
runat="server"
DataFile="~/App_Data/courses.mdb"
SelectCommand="SELECT * FROM [tblVendors] ORDER BY
[Vendor]">
</asp:AccessDataSource>
</HeaderTemplate>
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%#
Bind("Vendor") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="BasicCourseName"
HeaderText="BasicCourseName"
SortExpression="BasicCourseName" />
</Columns>
</asp:GridView>
<asp:AccessDataSource ID="AccessDataSource1" runat="server"
DataFile="~/App_Data/courses.mdb"
SelectCommand="SELECT * FROM
[qryCoursesByVendors]"></asp:AccessDataSource>
</form>
</body>
</html>
I don't know where to attach the code behind the form; on the dropdown list
changed event, or the page load event, or...? I am sorry if this is stupid,
but I can't seem to get it. Here is what I have in the code behind the form:
Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object,
ByVal e As System.EventArgs)
Dim ddlVendor As DropDownList
ddlVendor = Me.GridView1.FindControl("DropDownList1")
AccessDataSource1.FilterExpression = "VendorID = " &
ddlVendor.SelectedItem.Text
End Sub
I have also experimented with:
ddlVendor = CType(GridView1.TemplateControl.FindControl("DropDownList1"),
DropDownList)
I get the following error message:
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information about
the error and where it originated in the code.
Exception Details: System.NullReferenceException: Object reference not set
to an instance of an object.
Source Error:
Line 36: Dim ddlVendor As DropDownList
Line 37: ddlVendor = Me.GridView1.FindControl("DropDownList1")
Line 38: AccessDataSource1.FilterExpression = "VendorID = " &
ddlVendor.SelectedItem.Text
Line 39: End If
Is there any way to implement this type of thing, or is this a nightmare? I
am a beginning programmer, and I've already spent many days making only
incremental advances.
thanks in advance for your help and support.
mike
Click to expand...
Click to expand...
Click to expand...

hi ,
I am also doing the same thing in C#.net
i had the error at the line
DropDownList ddl1 = GridView1.HeaderRow.FindControl("ddl");
the error is
Cannot implicitly convert type 'System.Web.UI.Control' to
'System.Web.UI.WebControls.DropDownList'. An explicit conversion
exists (are you missing a cast?)

Please reply me
Sagar Kandekar
 
M

Mike

Hi, I'm sorry, I don't know C#...but the code I posted does work for me in
Visual Basic. I have heard there is a website that will convert visual basic
to C#; maybe google it? good luck!

[email protected] said:
OK OK for what it's worth, here is the result of my stupid 25 hours of
digging...sheesh!

This does not throw an error:

Dim ddlVendorFilter As DropDownList =
gvCourses.HeaderRow.FindControl("ddlVendor")

I have not tried including it in a Ctype expression, and I'm not sure it's
necessary...

The key is including the HeaderRow in the code, because the control is in
the headerRow...I guess this is "duh!" for many of you, but perhaps it may
help a fool like me save several days of frustration...good luck!

Mike said:
A little more update, I've also tried:
Click to expand...
Dim ddlVendorFilter As DropDownList =
CType(gvCourses.FindControl("ddlVendor"), DropDownList)
Click to expand...
MsgBox("ddlVendor Selected Value is" &
ddlVendorFilter.SelectedValue) 'Returns error
Click to expand...
:

I have a gridview that I want to basically convert to behavior like Excel
autofilter. I have created a dropdown list and put it into the header of the
gridview, but I can't seem to reference it correctly. I have been trolling
through the net and ms references for hours but I can't get it straight.
Click to expand...
Here is the html code:
Click to expand...
<%@ Page Language="VB" AutoEventWireup="false"
CodeFile="datagridtest4.aspx.vb" Inherits="datagridtest4" %>
Click to expand...
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
Click to expand...
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
Click to expand...
</div>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataSourceID="AccessDataSource1">
<Columns>
<asp:TemplateField HeaderText="Vendor" SortExpression="Vendor">
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text='<%#
Bind("Vendor") %>'></asp:TextBox>
</EditItemTemplate>
<HeaderTemplate>
<asp:DropDownList ID="DropDownList1" runat="server"
AutoPostBack="True"
DataSourceID="AccessDataSource1"
DataTextField="Vendor"
DataValueField="VendorID"
Click to expand...
onselectedindexchanged="DropDownList1_SelectedIndexChanged">
</asp:DropDownList>
<asp:AccessDataSource ID="AccessDataSource1"
runat="server"
DataFile="~/App_Data/courses.mdb"
SelectCommand="SELECT * FROM [tblVendors] ORDER BY
[Vendor]">
</asp:AccessDataSource>
</HeaderTemplate>
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%#
Bind("Vendor") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="BasicCourseName"
HeaderText="BasicCourseName"
SortExpression="BasicCourseName" />
</Columns>
</asp:GridView>
<asp:AccessDataSource ID="AccessDataSource1" runat="server"
DataFile="~/App_Data/courses.mdb"
SelectCommand="SELECT * FROM
[qryCoursesByVendors]"></asp:AccessDataSource>
</form>
</body>
</html>
Click to expand...
I don't know where to attach the code behind the form; on the dropdown list
changed event, or the page load event, or...? I am sorry if this is stupid,
but I can't seem to get it. Here is what I have in the code behind the form:
Click to expand...
Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object,
ByVal e As System.EventArgs)
Click to expand...
Dim ddlVendor As DropDownList
ddlVendor = Me.GridView1.FindControl("DropDownList1")
AccessDataSource1.FilterExpression = "VendorID = " &
ddlVendor.SelectedItem.Text
Click to expand...
End Sub
Click to expand...
I have also experimented with:
ddlVendor = CType(GridView1.TemplateControl.FindControl("DropDownList1"),
DropDownList)
Click to expand...
I get the following error message:
Click to expand...
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information about
the error and where it originated in the code.
Click to expand...
Exception Details: System.NullReferenceException: Object reference not set
to an instance of an object.
Click to expand...
Source Error:
Click to expand...
Line 36: Dim ddlVendor As DropDownList
Line 37: ddlVendor = Me.GridView1.FindControl("DropDownList1")
Line 38: AccessDataSource1.FilterExpression = "VendorID = " &
ddlVendor.SelectedItem.Text
Line 39: End If
Click to expand...
Is there any way to implement this type of thing, or is this a nightmare? I
am a beginning programmer, and I've already spent many days making only
incremental advances.
Click to expand...
thanks in advance for your help and support.
Click to expand...
mike
Click to expand...
Click to expand...

hi ,
I am also doing the same thing in C#.net
i had the error at the line
DropDownList ddl1 = GridView1.HeaderRow.FindControl("ddl");
the error is
Cannot implicitly convert type 'System.Web.UI.Control' to
'System.Web.UI.WebControls.DropDownList'. An explicit conversion
exists (are you missing a cast?)

Please reply me
Sagar Kandekar
Click to expand...
 
W

wesley tremayne

Thanks Mike, I have been struggling with the null reference exception
but didn't think to find the control in the HeaderRow, I was using Row.
Saved me some time.
 

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments. After that, you can post your question and our members will help you out.

Ask a Question

Similar Threads

Gridview update not working for AccessDataSource 6
gridview 0
Dropdownlist datasource dependency 13
Delete rows in Gridview 0
Gridview update not working (2.0) 0
Update gridview issue 2
Gridview Footer Help 1
can't update a GridView asp.net 2.0 0

Members online

Total: 337 (members: 1, guests: 336)
Robots: 273

Forum statistics

Threads
473,968
Messages
2,570,149
Members
46,695
Latest member
StanleyDri

Latest Threads

Top