Get data from the row of a Dropdown in a Gridview

Question

I have a Gridview with a column that has a DropDownList. I've binded this Dropdownlist with an event on the "SelectedIndexChanged". The problem is i can't get the value of a label of another column in the same row.

The code is the next:

protected void grid_OnSelectedIndexChanged(object sender, EventArgs e)
    {
        grdCredenciales.DataBind();

        var dropdown = (DropDownList)sender;
        var row = (GridViewRow)dropdown.NamingContainer;
        var label = (Label)row.FindControl("lblMatricula");

        var value = label.Text; // I get "" in this line.
    }

And in the grid i have:

<asp:ObjectDataSource ID="CredencialesDS" runat="server" />
<asp:GridView ID="grdCredenciales" runat="server" BackColor="White" DataSourceID="CredencialesDS"
    CssClass="DDGridView" RowStyle-CssClass="td" HeaderStyle-CssClass="th" CellPadding="6" AllowSorting="True"
    AllowPaging="True" AutoGenerateColumns="False" PageSize="10" OnRowDataBound="grdCredenciales_OnRowDataBound">
    <Columns>
        <asp:TemplateField>
            <HeaderTemplate>
               <asp:Label ID="Label7" ToolTip="Matrícula" runat="server" Text="Matrícula"/>
           </HeaderTemplate>
            <HeaderStyle HorizontalAlign="Left" Width="15%"/>
            <ItemStyle HorizontalAlign="Left" />
            <ItemTemplate>
                <asp:Label ID="lblMatricula" runat="server"><%# Eval("Matricula") %></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField>
            <HeaderTemplate>
               <asp:Label ID="Label19" ToolTip="Estado" runat="server" Text="Estado" />
           </HeaderTemplate>
            <HeaderStyle HorizontalAlign="Left" Width="15%"/>
            <ItemStyle HorizontalAlign="Left" />
            <ItemTemplate>
                <asp:DropDownList runat="server" ID="dpEstadoCredencial" AutoPostBack="True" OnSelectedIndexChanged="grid_OnSelectedIndexChanged" CssClass="comboEstado"/>
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

I don't know why, but label.text returns an empty string. As you can see, i am calling the DataBind before, so the label should have a value at this point.

Do you know how can i get the value i need from the label in another column?

Thanks for everyone.

Answer 1

Check the GridView's DataSource before you do the DataBind(). Since you're missing the full ASPX markup, I'm not sure if you're setting the data source programmatically or with a SqlDataSource.

In any case, what will happen often with programmatically-set Data Sources is that they disappear on a PostBack, and when you call that DataBind, you're really DataBinding it to null, which would explain why you're getting string.Empty ("") for the Label's Text property.