Nested GridView not binding

[RobertTheProgrammer]

Hi folks,

I've got another problem. Basically, I'm trying to use a nested GridView, however the nexted GridView displays no values (even though in debug I'm getting valid values into my DataSet. It's probably a binding issue somewhere, but I'm not sure where.

Here's the ASP (slightly edited to remove verbosity):

<asp:GridView ID="GridViewMain" runat="server" AutoGenerateColumns="False" BackColor="White" BorderColor="#999999"
    BorderStyle="None" Font-Names="Arial" BorderWidth="1px" CellPadding="3" DataSourceID="SqlDataSourceTrainingUnits"
    GridLines="Vertical" DataKeyNames="unit_id" OnRowUpdating="Validate_Data" OnRowCommand="grd_RowCommand"
    ShowFooter="True" OnRowDataBound="GridViewMain_RowDataBound">
    <FooterStyle BackColor="#CCCCCC" ForeColor="Black" />
    <Columns>
      <asp:TemplateField HeaderText="ID"> 
        <EditItemTemplate> 
          <asp:TextBox ID="unit_id" runat="server" Width="20px" Text='<%# Bind("unit_id") %>'></asp:TextBox> 
        </EditItemTemplate> 
        <ItemTemplate> 
          <asp:Label ID="unit_id" runat="server" Text='<%# Bind("unit_id") %>'></asp:Label> 
        </ItemTemplate>
      </asp:TemplateField>
      <asp:TemplateField HeaderText="Name">
        <EditItemTemplate> 
          <asp:TextBox ID="unit_name" runat="server" Text='<%# Bind("unit_name") %>'></asp:TextBox> 
        </EditItemTemplate> 
        <FooterTemplate> 
          <asp:TextBox ID="unit_name" runat="server" ></asp:TextBox> 
        </FooterTemplate> 
        <ItemTemplate> 
          <asp:Label ID="unit_name" runat="server" Text='<%# Bind("unit_name") %>'></asp:Label> 
        </ItemTemplate>
      </asp:TemplateField>
 
 
      <asp:TemplateField HeaderText="OtherStuff">
        <ItemTemplate> 
          <asp:GridView ID="GridViewNested" runat="server" AutoGenerateColumns="False" BackColor="White"
            BorderColor="#999999" BorderStyle="None" Font-Names="Arial" BorderWidth="1px" CellPadding="3" 
            DataSourceID='<%# GetDocuments(Convert.ToInt32(Eval("unit_id"))) %>'
            GridLines="Vertical" >
            <Columns>
                <asp:BoundField DataField="doc_name" HeaderText="Document Name" />
                <asp:BoundField DataField="version" HeaderText="Version" />
            </Columns>
            <RowStyle BackColor="#EEEEEE" ForeColor="Black" />
            <SelectedRowStyle BackColor="#008A8C" Font-Bold="True" ForeColor="White" />
            <PagerStyle BackColor="#999999" ForeColor="Black" HorizontalAlign="Center" />
            <HeaderStyle BackColor="#000084" Font-Bold="True" ForeColor="White" />
            <AlternatingRowStyle BackColor="Gainsboro" />
          </asp:GridView>
        </ItemTemplate>
      </asp:TemplateField>
 
 
    </Columns>
            <RowStyle BackColor="#EEEEEE" ForeColor="Black" />
            <SelectedRowStyle BackColor="#008A8C" Font-Bold="True" ForeColor="White" />
            <PagerStyle BackColor="#999999" ForeColor="Black" HorizontalAlign="Center" />
            <HeaderStyle BackColor="#000084" Font-Bold="True" ForeColor="White" />
            <AlternatingRowStyle BackColor="Gainsboro" />
</asp:GridView>
 

As you can see, the datasource for GridViewMain is an SQL data source and I have declared "unit_id" as the "DataKeyNames" parameter, which will be used in the nested GridView. Down in the nested GridView, called GridViewNested, the data source calls a method in the codebehind called GetDocuments.

Code for GetDocuments in the codebehind is as follows:

protected DataTable GetDocuments(int key)
{
    System.Data.DataTable tbl = new DataTable();
    DataColumn doc_namecol = new DataColumn("doc_name");
    tbl.Columns.Add(doc_namecol);
    DataColumn versioncol = new DataColumn("version");
    tbl.Columns.Add(versioncol);
 
    System.Data.OleDb.OleDbConnection ole1 = new System.Data.OleDb.OleDbConnection();
    ole1.ConnectionString = ConfigurationSettings.AppSettings["Training Connection String"];
    OleDbCommand cmd = ole1.CreateCommand();
    ole1.Open();
    OleDbDataReader dr;
    cmd.CommandText = "select doc_name, version, effective_date from training_documents where unit_id = " + key.ToString();
 
    dr = cmd.ExecuteReader();
    while (dr.Read())
    {
        if ((!dr.IsDBNull(0)) && (!dr.IsDBNull(1))))
        {
            DataRow drow = tbl.NewRow();
            drow["doc_name"] = dr.GetString(0).Trim();
            drow["version"] = dr.GetString(1).Trim();
            tbl.Rows.Add(drow);
        }
    }
 
    dr.Close();
    cmd.Dispose();
    ole1.Close();
    ole1.Dispose();
 
    return tbl;
}
 

I've run the above code in debug mode and tbl is being populated with good data, but for unknown reasons, it's not being displayed in the nested GridView. (The main/parent GridView displays just fine).

Any help is greatly appreciated.

Robert

[nateraaaa]

Are you assigning the datatable as the datasource for your nested grid view? Please post the code where you assign the datasource for the nested grid view.

Nathan

[RobertTheProgrammer]

It's right there in the code I listed:

In the nested GridView, the datasource is in the line:

DataSourceID='<%# GetDocuments(Convert.ToInt32(Eval("unit_id"))) %>'
 

And I have shown the full method for GetDocuments.

In any case, the solution was not forthcoming so I found another way to solve my problem. I assigned the datasource in the codebehind instead.

Thanks anyway.

Robert

[nateraaaa]

It's right there in the code I listed:

In the nested GridView, the datasource is in the line:

DataSourceID='<%# GetDocuments(Convert.ToInt32(Eval("unit_id"))) %>'
 

And I have shown the full method for GetDocuments.

In any case, the solution was not forthcoming so I found another way to solve my problem. I assigned the datasource in the codebehind instead.

Thanks anyway.

Robert

I believe that gridview DataSourceId expects the value to be set to an instance of SqlDataSource (or other data source type such as ODBC). You were trying to set the DataSourceId = to a datatable. In the code behind this is valid because to set the datasource property of the gridview = to a datatable. Here is a helpful link on binding data usig datasource controls.
http://msdn.microsoft.com/en-us/library/ms228089.aspx

Nathan