Classic ASP.NET Delete event is not invoked in dynamically generated datagrid control delete link

问题

I have a classic asp.net application. I have a datagrid user control with the MarkUp data source as:

<asp:SqlDataSource ID="DataSource" runat="server" DeleteCommand="UPDATE tblLSystem SET LS_Deleted='1' WHERE LS_ID=@LS_ID"
    SelectCommand="SELECT * FROM vwLSystem WHERE LS_Deleted='0' order by LS_CreatedOn" OnSelected="DataSource_Selected" OnDeleted="DataSource_Selected" OnDeleting = "DataSource_Deleting">
    <DeleteParameters>
        <asp:Parameter Name="LS_ID" Type="Object" />
    </DeleteParameters>
</asp:SqlDataSource>

The delete linkbutton template is declared as:

<asp:TemplateField HeaderText="" SortExpression="" Visible="True"> 
    <ItemTemplate>
       <asp:LinkButton ID="btnDelete" CommandName="Delete" runat="server" Text="Delete" />
    </ItemTemplate>            
</asp:TemplateField>

The code behind class name is "class StudLSystemGrid". And the DataSource_Deleting event function in this class is:

protected void DataSource_Deleting(object sender, SqlDataSourceCommandEventArgs e)
{
}

This user control is used in another asp.net page. It is registered in the page as:

<%@ Register Src="Controls/LSystemGrid.ascx" TagName="LSystemGrid" TagPrefix="uc4" %>

In the same page it is used to create one user control statically like this:

  <uc4:LSystemGrid ID="LSystemGrid1" runat="server" ShowAuditFields="false" />

I also need to create multiple user controls depending on the situation dynamically in code behind. So I have a placeholder in MarkUp page:

  <asp:PlaceHolder id="PlaceHolder1" runat="server"/>

And same codes in code behind to generate the user control:

    ucLControl =
      LoadControl("Controls/LSystemGrid.ascx")
      as StudLSystemGrid;
    ucLControl.ID = "LSystemGridPD" + i.ToString();
    ucLControl.ShowAuditFields = false;
    ucLControl.SqlDataSource.ConnectionString = ConnectionManager.ConnectionString;
    ucLControl.DataBind();
    PlaceHolder1.Controls.Add(ucLControl);

The statically generated user control works fine. Clicking the delete link can invoke the function "DataSource_Deleting" mentioned earlier. However the dynamically generated user control does not work. The function "DataSource_Deleting" is not hit and the item can not be deleted.

The html source for the delete link in statically markup user control is:

       <a onclick="{alert('There'); return false;} ;" 
id="ctl00_PageBody_LSystemGrid1_BaseGrid_ctl02_btnDelete" 
href="javascript:__doPostBack('ctl00$PageBody$LSystemGrid1$BaseGrid$ctl02$btnDelete','')">Delete</a>

For dynamically generated user control from code behind is:

       <a onclick="{alert('Here'); return false;} ;" 
id="LSystemGridPD0_BaseGrid_ctl13_btnDelete" 
href="javascript:__doPostBack('LSystemGridPD0$BaseGrid$ctl13$btnDelete','')">Delete</a>

Anybody knows what is wrong here? How can we determine the datagrid is in delete mode when using delete linkbutton in this way in code behind?

Thanks

Update: The user control is dynamically generated from -

protected void Page_Load(object sender, EventArgs e)
{
    PreRender += LSystem_PreRender;    
}

void LSystem_PreRender(object sender, EventArgs e)
{
    ucLControl =
      LoadControl("Controls/LSystemGrid.ascx")
      as StudLSystemGrid;
    ucLControl.ID = "LSystemGridPD0";
    ucLControl.ShowAuditFields = false;
    ucLControl.SqlDataSource.ConnectionString = ConnectionManager.ConnectionString;
    ucLControl.DataBind();
    PlaceHolder1.Controls.Add(ucLControl);
}

Update 2:

Update 2: The user control is dynamically generated from -

protected void Page_Load(object sender, EventArgs e)
{
    ucLControl =
      LoadControl("Controls/LSystemGrid.ascx")
      as StudLSystemGrid;
    ucLControl.ID = "LSystemGridPD0";
    ucLControl.ShowAuditFields = false;
    ucLControl.SqlDataSource.ConnectionString = ConnectionManager.ConnectionString;
    ucLControl.EnableViewState = true;
    ucLControl.DataBind();
    PlaceHolder1.Controls.Add(ucLControl);
}

回答1:

Found out the problem. Data has been bound after

   ucLControl = LoadControl("Controls/LSystemGrid.ascx")       as StudLSystemGrid;

Invoking ucLControl.DataBind(); again wipes out the bounded attributes.

After removed the line "ucLControl.DataBind();", the delete event can be triggered.

来源：https://stackoverflow.com/questions/20779650/classic-asp-net-delete-event-is-not-invoked-in-dynamically-generated-datagrid-co

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