[DotNetDevelopment] Question about DataKeyNames

[Daniel G. Samborski]

Hi, I'm Daniel and I'm new in this group, Sorry, but my english isn't good. I have a problem when I use DataKeyNames in C#, I use SQL server 2000 whit UniqueIdentifier in an ID register. This is the code of GridView <asp:GridView DataKeyNames="IdSitio" ID="grdListadoDeSitio" runat="server" Caption="Listado de todos los sitios" AutoGenerateColumns="False" AutoGenerateDeleteButton="True" BackColor="LightGoldenrodYellow" BorderColor="Tan" BorderWidth="1px" CellPadding="2" ForeColor="Black" GridLines="None" Font-Size="X-Small">                 <Columns>                     <asp:BoundField DataField="IdSitio" HeaderText="IdSitio" ReadOnly="True" Visible="False" />                     <asp:BoundField DataField="Nombre" HeaderText="Sitio" ReadOnly="True" />                     <asp:BoundField DataField="URL" HeaderText="URL" ReadOnly="True" />                     <asp:BoundField DataField="Comentario" HeaderText="Comentario" ReadOnly="True" />                 </Columns>                 <SelectedRowStyle BackColor="DarkSlateBlue" ForeColor="GhostWhite" />                 <PagerStyle BackColor="PaleGoldenrod" ForeColor="DarkSlateBlue" HorizontalAlign="Center" />                 <HeaderStyle BackColor="Tan" Font-Bold="True" />                 <AlternatingRowStyle BackColor="PaleGoldenrod" /> </asp:GridView> And I use to read the IdSitio this code: Guid id = new Guid(grdListadoDeSitio.SelectedDataKey["IdSitio"].ToString()); oSitiosAmigos.LoadByPrimaryKey(id); But, I have this error message: Object reference not set to an instance of an object. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.NullReferenceException: Object reference not set to an instance of an object. Source Error: Line 52:     { Line 53:         // Guid id= new Guid(grdListadoDeSitio.Rows[e.RowIndex].Cells[1].Text); Line 54:         Guid id = new Guid(grdListadoDeSitio.SelectedDataKey["IdSitio"].ToString()); Line 55:         oSitiosAmigos.LoadByPrimaryKey(id); Line 56:         oSitiosAmigos.MarkAsDeleted();   Source File: c:\Documents and Settings\Daniel\Mis documentos\Visual Studio 2005\Projects\elpeloenelhuevo\elpeloblog\Altas\SitiosAmigos.aspx.cs    Line: 54 Stack Trace: [NullReferenceException: Object reference not set to an instance of an object.]    Altas_SitiosAmigos.grdListadoDeSitio_RowDeleting(Object sender, GridViewDeleteEventArgs e) in c:\Documents and Settings\Daniel\Mis documentos\Visual Studio 2005\Projects\elpeloenelhuevo\elpeloblog\Altas\SitiosAmigos.aspx.cs:54    System.Web.UI.WebControls.GridView.OnRowDeleting(GridViewDeleteEventArgs e) +131    System.Web.UI.WebControls.GridView.HandleDelete(GridViewRow row, Int32 rowIndex) +732    System.Web.UI.WebControls.GridView.HandleEvent(EventArgs e, Boolean causesValidation, String validationGroup) +1067    System.Web.UI.WebControls.GridView.RaisePostBackEvent(String eventArgument) +214    System.Web.UI.WebControls.GridView.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +31    System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +32    System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +244    System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3840 If I use Guid id= new Guid(grdListadoDeSitio.Rows[e.RowIndex].Cells[1].Text); with columns visible=true I can read the ID... Can help my pleas. Thankyou