Problems with Row_Deleting in GridView

Hi,

I'm having trouble deleting a row in GridView.  The error message states:  Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index

The problem I think I'm having is finding the right code to return my datakeys.

My code is below.

Any help someone could provide would be great.

Thanks.

<asp:GridView ID="publications" runat="server"  
            AutoGenerateColumns="False"
           Width="642px" onRowDeleting="publications_RowDeleting" DataKeyNames="subjectID, publicationID">
            <Columns>
            <asp:BoundField DataField="publicationID" HeaderText="Publication ID"  ReadOnly="true" />
                <asp:TemplateField HeaderText="Subject Name">
                    <EditItemTemplate>
                        <asp:TextBox ID="subjectName" runat="server" Text='<%# Bind("subjectName") %>'></asp:TextBox>
                    </EditItemTemplate>
                    <ItemTemplate>
                        <asp:Label ID="subjectName" runat="server" Text='<%# Bind("subjectName") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:BoundField DataField="subjectID" ReadOnly="true"/>
                <asp:CommandField ShowDeleteButton="True" />
            
            </Columns>
        </asp:GridView>
 
 
 
protected void publications_RowDeleting(Object sender, GridViewDeleteEventArgs e)
        {
            string publicationID = publications.DataKeys[publications.SelectedIndex].Values["publicationID"].ToString();
            string subjectID = publications.DataKeys[publications.SelectedIndex].Values["subjectID"].ToString();
 
        SqlConnection conn;
        SqlCommand comm;
 
        string connectionString = ConfigurationManager.ConnectionStrings["publications"].ConnectionString;
 
        conn = new SqlConnection(connectionString);
 
        comm = new SqlCommand("Delete subjects2pub where publicationID = @publicationID and subjectID = @subjectID ", conn);
        comm.Parameters.AddWithValue("@publicationID", publicationID);
        comm.Parameters.AddWithValue("@subjectID", subjectID);
        try
        {
            conn.Open();
            comm.ExecuteNonQuery();
            BindGrid();
        }
 
        catch
        {
            MessageBox.Text = "There was an error deleting this record.";
        }
         finally
        {
            conn.Close();
        }
 
    }
 
//partial code from BindGrid() to show that I believe I've set up the DataKeyNames correctly:
BindGrid()
publications.DataKeyNames = new string[] { "publicationID" };
publications.DataKeyNames = new string[] { "subjectID" };

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Finlay11Asked:
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guru_samiCommented:
You are deleting the row and a=might be the Row is not selected i.e. SelectedIndex=-1
Use e.RowIndex like below:

string publicationID = publications.DataKeys[e.RowIndex].Values["publicationID"].ToString();
string subjectID = publications.DataKeys[e.RowIndex].Values["subjectID"].ToString();
 
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ppittleCommented:
What's the DataSource for hte GridView?  If you configure your GridView to use a SqlDataSource or ObjectDataSource you get deleting more or less for free and it you generally don't have to worry about these head aches.  

If you're unfimiliar with SqlDataSources, here's a good tutorial:  http://www.asp.net/learn/data-access/tutorial-47-cs.aspx
0
Finlay11Author Commented:
Now I get the error:  Object reference not set to an instance of an object.
0
guru_samiCommented:
looks due to this:
publications.DataKeyNames = new string[] { "publicationID" };
publications.DataKeyNames = new string[] { "subjectID" };

Try this:
publications.DataKeyNames = new string[] { "publicationID" ,"subjectID" };
0

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Finlay11Author Commented:
That was it!  Thanks so much
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