Velocity Reviews - Dropdownlist in template column to fire a SelectedIndexChanged event?

Velocity Reviews (http://www.velocityreviews.com/forums/index.php)

- ASP .Net Datagrid Control (http://www.velocityreviews.com/forums/f60-asp-net-datagrid-control.html)

- - Dropdownlist in template column to fire a SelectedIndexChanged event? (http://www.velocityreviews.com/forums/t761008-dropdownlist-in-template-column-to-fire-a-selectedindexchanged-event.html)

Dropdownlist in template column to fire a SelectedIndexChanged event?

I have a ddl in a template column of a data grid. The ddl displays
fine. I'm having no luck though getting an event to fire when the
user selects a new value in a row's ddl. I can put a button in the
template and get the command event for the grid, but nothing for the
ddl.

I have the ddl set to use view state and to autopostback.

Thanks

Mark

RE: Dropdownlist in template column to fire a SelectedIndexChanged event?

Hi Mark,

As for the Datagrid's nested dropdownlist's postback issue, I think we can
check the following things first:
1. Has the dropdownlist been set as AutoPostBack= true?

2. How do you wireup the selectedIndexchanged event handler for the
dropdownlist?

Here is a test page , you may have a look to see whether there are any
difference:

=============aspx=============
<HTML>
<HEAD>
<title>ddlgrid</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema"
content="http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body>
<form id="Form1" method="post" runat="server">
<table width="100%" align="center">
<tr>
<td>
<asp:DataGrid id="dgMain" runat="server" AutoGenerateColumns="False">
<Columns>
<asp:TemplateColumn HeaderText="DropDownList">
<ItemTemplate>
<asp:DropDownList AutoPostBack="True" id="lstItems"
runat="server" OnSelectedIndexChanged="lstItems_SelectedIndexChan ged"
SelectedIndex='<%# Container.DataItem %>'>
<asp:ListItem Value="aaaa" Selected="True">aaaa</asp:ListItem>
<asp:ListItem Value="bbbb">bbbb</asp:ListItem>
<asp:ListItem Value="cccc">cccc</asp:ListItem>
<asp:ListItem Value="dddd">dddd</asp:ListItem>
</asp:DropDownList>
</ItemTemplate>
</asp:TemplateColumn>
</Columns>
</asp:DataGrid>
</td>
</tr>
<tr>
<td></td>
</tr>
</table>
</form>
</body>
</HTML>

======code behind==============
public class ddlgrid : System.Web.UI.Page
{
protected System.Web.UI.WebControls.DataGrid dgMain;

private void Page_Load(object sender, System.EventArgs e)
{
// Put user code to initialize the page here
if(!IsPostBack)
{
int[] values = new int[]{0,1,2,3,2,3,1,2};
dgMain.DataSource = values;
dgMain.DataBind();
}

}

#region Web Form Designer generated code
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
InitializeComponent();
base.OnInit(e);
}

/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.Load += new System.EventHandler(this.Page_Load);

}
#endregion

protected void lstItems_SelectedIndexChanged(object sender,
System.EventArgs e)
{
System.Web.UI.WebControls.DropDownList lst =
(System.Web.UI.WebControls.DropDownList)sender;
Response.Write("<br>New selected index of " + lst.ID + "is " +
lst.SelectedIndex );
}
}
================================================== =

Thanks.

Regards,

Steven Cheng
Microsoft Online Support

Get Secure! www.microsoft.com/security
(This posting is provided "AS IS", with no warranties, and confers no
rights.)

Get Preview at ASP.NET whidbey
http://msdn.microsoft.com/asp.net/whidbey/default.aspx

Re: Dropdownlist in template column to fire a SelectedIndexChanged event?

Hi Steven,

Your example works. Is there a way though that I can get data from the
datagrid row to the event handler? That's why I was looking a getting
a datagrid event to fire. I guess I could encode what I need into the
list for each row. BTW, I'm not using the grid's
datasource/dataadapter for doing updates.

Thanks, Mark

Re: Dropdownlist in template column to fire a SelectedIndexChanged event?

Hi Mark,

Since the dropdownlist control is nested in the each DataGridItem's certain
cell. We can use the "Control" 's "Parent" property to reference its parent
control. Then in the dropdownlist's selectedindexchanged event, we can use
the following code to reference the DataGridItem :

protected void lstItems_SelectedIndexChanged(object sender,
System.EventArgs e)
{
System.Web.UI.WebControls.DropDownList lst =
(System.Web.UI.WebControls.DropDownList)sender;
DataGridItem dgi = lst.Parent.Parent as DataGridItem;

if(dgi != null)
{
Response.Write("<br>ItemIndex: " + dgi.ItemIndex );
Response.Write("<br>Cells Count: " + dgi.Cells.Count);
}

}

Then, if you want to retrieve the values in other cells, just search the
certain SubControl in the DataGridItem's other Cells.

Thanks.'

Regards,

Steven Cheng
Microsoft Online Support

Get Secure! www.microsoft.com/security
(This posting is provided "AS IS", with no warranties, and confers no
rights.)

Get Preview at ASP.NET whidbey
http://msdn.microsoft.com/asp.net/whidbey/default.aspx

Re: Dropdownlist in template column to fire a SelectedIndexChanged event?

Thanks again! That does the trick.

Re: Dropdownlist in template column to fire a SelectedIndexChanged event?