Wiring a GridView Programmatically - Is It Possible??

T

Tomasz

Hello Developers,

Here is interesting problem I just came across: how do I wire a GridView
control programmatically?

Here is my sample code using Object Data Source:

protected void Page_Load(object sender, EventArgs e)
{
ObjectDataSource ods = new ObjectDataSource("MyTestTableAdapter",
"GetData");
GridView1.DataSource = ods;
GridView1.DataBind();
}

My GridView1 has auto generated Edit and Delete buttons, and of course, they
do not work. An attempt to modify data causes "The GridView 'GridView1'
fired event RowEditing which wasn't handled" exception.

Ok, I know that it would not update anyway, since UpdateMethod and
UpdateParameters properties are not set, but it seems that it fails before
even trying.

The same control wired using a designer (DataSourceID property) behaves
differently, that is: text boxes are being rendered, "Edit" button change to
"Cancel" and so on.

It almost seems that it is not possible to achieve the same effect
programmatically *without handling all the required events*.

Please prove me if I am wrong. I hope I am wrong, and it is not a sign a new
paradigm in MS component development: use a designer or you are screwed.

Thank you,

Tomasz

**Note: I know how to bind GridView1 programatically using templates and
handling all the events like RowEditing or RowDeleting.
 
W

Walter Wang [MSFT]

Hi Tomasz,

This is really an interesting question. I understand that your objective
here is to programmatically create an ObjectDataSource instance at run-time
and want to bind your GridView to it. So far you're seeing that the data
displays but editing it will require you manually handle the OnRowEditing
event.

With Reflector (http://www.aisto.com/roeder/dotnet/), you could see that
GridView.OnRowEditing will throw the exception if the DataSourceID property
is not set.

To workaround this limit, I'm afraid you will have to associate the
ObjectDataSource with the GridView using DataSourceID property instead of
DataSource. To do that, we will also have to add the ObjectDataSource to
the same container of GridView:

<%@ Page Language="C#" %>

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

<script runat="server">

protected void Page_Load(object sender, EventArgs e)
{
ObjectDataSource ods = new
ObjectDataSource("DataSet1TableAdapters.CategoriesTableAdapter", "GetData");
ods.OldValuesParameterFormatString = "Original_{0}";
ods.UpdateMethod = "Update";
ods.UpdateParameters.Add("CategoryName", TypeCode.String, null);
ods.UpdateParameters.Add("Original_CategoryID", TypeCode.Int32,
null);
ods.ID = "ods1";
form1.Controls.Add(ods);
GridView1.DataSourceID = ods.ID;
}
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:GridView ID="GridView1" runat="server" AllowPaging="True"
AllowSorting="True"
AutoGenerateColumns="False" DataKeyNames="CategoryID">
<Columns>
<asp:CommandField ShowEditButton="True" />
<asp:BoundField DataField="CategoryID"
HeaderText="CategoryID" InsertVisible="False"
ReadOnly="True" SortExpression="CategoryID" />
<asp:BoundField DataField="CategoryName"
HeaderText="CategoryName" SortExpression="CategoryName" />
</Columns>
</asp:GridView>
</div>
</form>
</body>
</html>

Hope this helps.

Sincerely,
Walter Wang ([email protected], remove 'online.')
Microsoft Online Community Support

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T

Tomasz

Hello Walter,

I have started using the method you suggested.
However, I discovered an interesting problem I decided to described here for
the record.
GridView and DetailsView controls bound that way behave slightly
differently.

DetailsView.DataSourceID should be specified early, in Page_PreLoad event.
Otherwise some validators attached to DetailsView template controls may not
work properly.

On the other hand, GridView.DataSourceID must be specified in Page_Load
event, *even during PostBack*. Otherwise GridView will not refresh data.
That is, it will not call ExecuteSelect() on the
DataSourceControl.DataSourceView.

Tomasz J
 
W

Walter Wang [MSFT]

Hi Tomasz,

Thank you for sharing your findings with the community.

Yes how to programmatically set DataSourceID is not documented and there
might be some difference in different controls.

Regards,
Walter Wang ([email protected], remove 'online.')
Microsoft Online Community Support

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