Passing parameter from gridview to sqldatasource error

Question

I'm using gridview with edit/delete. When the user clicks on "Edit" I need to pass a value from one column (100mPLot) to a datasource that would populate a dropdownlist of another column (SubPlot). This is what I have:

<asp:BoundField DataField="100mPlot" HeaderText="100m plot" 
     SortExpression="100mPlot" ReadOnly="True" />
<asp:TemplateField HeaderText="SubPlot" SortExpression="SubPlot">
    <EditItemTemplate>                            
        <asp:DropDownList ID="DropDownList1" runat="server" 
            DataSourceID="dsSubPlotNames" 
            DataTextField="SiteName" DataValueField="SiteID" 
            SelectedValue='<%# Bind("SiteID") %>'
        >
        </asp:DropDownList>
        <asp:SqlDataSource ID="dsSubPlotNames" runat="server" 
            ConnectionString="<%$ ConnectionStrings:WERCMTX %>" SelectCommand='exec [339_PPM].usp_SubPlotNames_Select null, @100mPlotName;'
            CancelSelectOnNullParameter="False">                                
            <SelectParameters>
                <asp:ControlParameter ControlID="GridView1" DefaultValue='<%# Eval("100mPlot") '
                    Name="100mPlotName" PropertyName="SelectedValue" />
             </SelectParameters>
         </asp:SqlDataSource>
     </EditItemTemplate>
          <ItemTemplate>
              <asp:Label ID="Label3" runat="server" Text='<%# Bind("SubPlot") %>'></asp:Label>
     </ItemTemplate>                        
 </asp:TemplateField>

Unfortunately, I get this error with the Eval("100mPlot"):

Databinding expressions are only supported on objects that have a DataBinding event. System.Web.UI.WebControls.ControlParameter does not have a DataBinding event.

How do I fix this? Thanks,

EDIT:

I moved it to code behind and handled it in RowDataBound after creating a hidden label tag containing the value of the previous column.

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
     if (e.Row.RowType == DataControlRowType.DataRow && (e.Row.RowState & DataControlRowState.Edit) == DataControlRowState.Edit)
     { 
         Label lbl100mPlot = (Label)e.Row.FindControl("lbl100mPlot");
         SqlDataSource dsPlotNames = (SqlDataSource)e.Row.FindControl("dsSubPlotNames");
         dsPlotNames.SelectParameters.Clear();
         dsPlotNames.SelectParameters.Add("100mPlotSiteID", null);
         dsPlotNames.SelectParameters.Add("100mPlotName", lbl100mPlot.Text);               
    }
}

My next problem is this error:

Databinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control.

Exception Details: System.InvalidOperationException: Databinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control.

Source Error:

[No relevant source lines]

I'm not sure what's causing it.

fenix2222 · Accepted Answer · 2012-05-22 22:25:55Z

1

I dont think you can do it this way. You can handle RowEditing event in code behind and manually adjust your SqlDataSource to display correct data. Also, move SqlDataSoruce out of your grid.

answered May 22, 2012 at 22:25

fenix2222

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1 Comment

dam Over a year ago

Thanks, I moved it to code behind and was able to solve the parameter passing problem. But now I'm facing a different issue.

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