How to set SelectedValue of DropDownList in GridView EditTemplate

Question

I am trying to do this as asked earlier. The only difference that I found is additional List item that was included in above code.

I tried to use AppendDataBoundItems=true but it is still not working. I also want to set the its default value to the value that was being displayed in label of itemtemplate i.e. DropDownList's SelectedValue='<%# Eval("DepartmentName") %>' but thie property is not available to me in dropdownlist. What could be the reason. ??

<EditItemTemplate>
    <asp:DropDownList ID="ddlDepartment_Edit" runat="server" 
        DataSourceID="dsDepartment_Edit" DataTextField="DepartmentName" 
        DataValueField="PK_DepartmentId">
    </asp:DropDownList>
    <asp:SqlDataSource ID="dsDepartment_Edit" runat="server" 
        ConnectionString="<%$ ConnectionStrings:BlackHillsConnect %>"  
        ProviderName="System.Data.SqlClient" SelectCommand="sp_GetDepartmentDropDown" 
        SelectCommandType="StoredProcedure">
    </asp:SqlDataSource>                                 
</EditItemTemplate>
<ItemTemplate>
    <asp:Label ID="lblDepartmentName" runat="server" Text='<%# Eval("DepartmentName") %>' >
    </asp:Label>
</ItemTemplate>   

I am using GridView

Answer 1

DataValueField seems to be wrong - shouldn't it be DepartmentId? Similarly, you need to have SelectedValue='<%# Eval("**DepartmentId**") %>' - DepartmentName would be the SeletectText.

Answer 2

The use of the GridView_DataBound event handler solves the problem.

In your case you will need to add a HiddenField to store the PK_DepartmentId value:

<asp:GridView ID="gvExample" runat="server" AutoGenerateColumns="False" OnDataBound="gvExample_DataBound">
  <Columns>
    <asp:TemplateField HeaderText="Department">
      <EditItemTemplate>
        <asp:DropDownList ID="ddlDepartment_Edit" runat="server" DataSourceID="dsDepartment_Edit"
          DataTextField="DepartmentName" DataValueField="PK_DepartmentId">
        </asp:DropDownList>
        <asp:HiddenField ID="hfDepartmentId" runat="server" Value='<%# Bind("PK_DepartmentId") %>' />
        <asp:SqlDataSource ID="dsDepartment_Edit" runat="server" ConnectionString="<%$ ConnectionStrings:BlackHillsConnect %>"
          ProviderName="System.Data.SqlClient" SelectCommand="sp_GetDepartmentDropDown" SelectCommandType="StoredProcedure">
        </asp:SqlDataSource>
      </EditItemTemplate>
      <ItemTemplate>
        <asp:Label ID="lblDepartmentName" runat="server" Text='<%# Eval("DepartmentName") %>'>
        </asp:Label>
      </ItemTemplate>
    </asp:TemplateField>
    <asp:CommandField ShowEditButton="True" ButtonType="Button" />
  </Columns>
</asp:GridView>

protected void gvExample_DataBound(object sender, EventArgs e)
{
  foreach (GridViewRow gvRow in gvExample.Rows)
  {
    DropDownList ddlDepartment = gvRow.FindControl("ddlDepartment_Edit") as DropDownList;
    HiddenField hfDepartmentId = gvRow.FindControl("hfDepartmentId") as HiddenField;

    if (ddlDepartment != null && hfDepartmentId != null)
    {
      ddlDepartment.SelectedValue = hfDepartmentId.Value;
    }
  }
}