Displaying images in the DataGrid

[Henrik Skak Pedersen]

Hi,

I have a Datasource which contains strings fields and a binary field
containing a image. How do I display them in the DataGrid using data
binding? Normally in Windows Forms Applications is it very easy to bind to
image controls, but do I do it in ASP?

Thanks
Henrik.

 

[Walter Wang [MSFT]]

Hi Henrik,

To display a image in ASP.NET server control DataGrid, you need to set a
column to use template and use an image control inside it, then in
ItemDataBound event, retrieve the image's binary data and output it. Since
normally an image control's ImageUrl refers to a URL of a static image
file, it can also refer to a webform that outputs dynamic image binary data:

#Retrieving Images from SqlServer and displaying in a DataGrid - ASP .NET:
ASP Alliance
http://aspalliance.com/articleViewer.aspx?aId=141&pId=


Another approach without creating a webform to read the image data is to
create a custom image control and output the image data directly in its
code:

#Display Images in a DataGrid Directly from Memory
http://www.eggheadcafe.com/articles/20050911.asp


Hope this helps.

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

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[Henrik Skak Pedersen]

Hi Walter,

Thank you very much for your reply. I have decided to use a mix of the two
examples, which you can see below. Is this a good approach?

Thanks
Henrik.

On my page I have created a TemplateField:
<asp:TemplateField>
<ItemTemplate>
<asp:Image ID="Image1" Width="75" Height="100"
ImageUrl='<%# GetURL(DataBinder.Eval(Container.DataItem,
"Picture") as System.Byte[]) %>' Runat=server />
</ItemTemplate>
</asp:TemplateField>

Then I have created a GetURL method on my page:
protected string GetURL(System.Byte[] image)
{
if (image != null && image.Length > 0)
{
string guidString = Guid.NewGuid().ToString();
Session[guidString] = image;
return "GetImage.aspx?ImageId=" + guidString;
}
return String.Empty;
}

and then finally a new page called GetImage.aspx:
protected void Page_Load(object sender, EventArgs e)
{
string imageId = Request.QueryString.Get("ImageId");
System.Byte[] imageBytes = (System.Byte[])Session[imageId];
Session[imageId] = null;
using (MemoryStream ms = new MemoryStream(imageBytes))
{
using (Bitmap image = (Bitmap)System.Drawing.Bitmap.FromStream(ms))
{
image.Save(Response.OutputStream,
System.Drawing.Imaging.ImageFormat.Jpeg);
imageBytes = null;
}
}
}

 

[Walter Wang [MSFT]]

Hi Henrik,

Thanks for the update.

I can see you first put the image data into session then retrieve it in
another webpage. I think this approach should be fine. Just don't forget to
set Response.ContentType before writing to Response.OutputStream.


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

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