How to Update and Delete the Rows of Gridview using LINQ to SQL in asp.net

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Hi Guys , I tried in different ways. I am learning to Linq and Edm. I have a gridview with Edit, Update Deleting Events. If i am trying to update the row , i go the errors.

Source Code of Gridview :

XML

<asp:GridView ID="GridView1" runat="server" BackColor="White" BorderColor="#E7E7FF" BorderStyle="None" BorderWidth="1px" CellPadding="3" GridLines="Horizontal" AutoGenerateColumns="false" OnRowCancelingEdit="GridView1_RowCancelingEdit" OnRowDeleting="GridView1_RowDeleting" OnRowEditing="GridView1_RowEditing" OnRowUpdating="GridView1_RowUpdating"> <AlternatingRowStyle BackColor="#F7F7F7" /> <FooterStyle BackColor="#B5C7DE" ForeColor="#4A3C8C" /> <HeaderStyle BackColor="#4A3C8C" Font-Bold="True" ForeColor="#F7F7F7" /> <PagerStyle BackColor="#E7E7FF" ForeColor="#4A3C8C" HorizontalAlign="Right" /> <RowStyle BackColor="#E7E7FF" ForeColor="#4A3C8C" /> <SelectedRowStyle BackColor="#738A9C" Font-Bold="True" ForeColor="#F7F7F7" /> <SortedAscendingCellStyle BackColor="#F4F4FD" /> <SortedAscendingHeaderStyle BackColor="#5A4C9D" /> <SortedDescendingCellStyle BackColor="#D8D8F0" /> <SortedDescendingHeaderStyle BackColor="#3E3277" /> <Columns> <asp:TemplateField HeaderText="Edit"> <ItemTemplate> <asp:LinkButton ID="lbnEdit" runat="server" CausesValidation="False" CommandName="Edit" Text="Edit"></asp:LinkButton> </ItemTemplate> <EditItemTemplate> <asp:LinkButton ID="lbnUpdate" runat="server" CausesValidation="True" CommandName="Update" Text="Update" OnClientClick="return confirm('Update?')"></asp:LinkButton> <asp:LinkButton ID="lbnCancel" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel"></asp:LinkButton> </EditItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Delete"> <ItemTemplate> <asp:LinkButton ID="lbnDelete" runat="server" CausesValidation="False" CommandName="Delete" Text="Delete" OnClientClick="return confirm('Delete?')"></asp:LinkButton> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="SNO"> <ItemTemplate> <asp:Label ID="lblSno" runat="server" Text='<%# Bind("SNO") %>'>'></asp:Label> </ItemTemplate> <%-- <EditItemTemplate> <asp:TextBox ID="txtSno" runat="server" Text='<%# Bind("SNO") %>'>' ></asp:TextBox> </EditItemTemplate>--%> </asp:TemplateField> <asp:TemplateField HeaderText="BATCHNO"> <ItemTemplate> <asp:Label ID="lblBatch" runat="server" Text='<%# Bind("BATCHNO") %>'>'></asp:Label> </ItemTemplate> <EditItemTemplate> <asp:TextBox ID="txtBatch" runat="server" Text='<%# Bind("BATCHNO") %>'>' ></asp:TextBox> </EditItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="JOBNO"> <ItemTemplate> <asp:Label ID="lblJobNo" runat="server" Text='<%# Bind("JOBNO") %>'>'></asp:Label> </ItemTemplate> <EditItemTemplate> <asp:TextBox ID="txtJobNo" runat="server" Text='<%# Bind("JOBNO") %>'>' ></asp:TextBox> </EditItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="LOTNO"> <ItemTemplate> <asp:Label ID="lblLotNo" runat="server" Text='<%# Bind("LOTNO") %>'>'></asp:Label> </ItemTemplate> <EditItemTemplate> <asp:TextBox ID="txtLotNo" runat="server" Text='<%# Bind("LOTNO") %>'>' ></asp:TextBox> </EditItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="MODIFIEDDATE"> <ItemTemplate> <asp:Label ID="lblModifiedDate" runat="server" Text='<%# Bind("MODIFIEDDATE") %>'>'></asp:Label> </ItemTemplate> <EditItemTemplate> <asp:TextBox ID="txtModifiedDate" runat="server" Text='<%# Bind("MODIFIEDDATE") %>'>' ></asp:TextBox> </EditItemTemplate> </asp:TemplateField> </Columns> </asp:GridView>

DataBinding to Gridview :

C#

protected void Page_Load(object sender, EventArgs e)
   {
    binddata();
    }

C#

private void binddata()
    {
        LinqDataContext ld = new LinqDataContext();

        var query = (from p in ld.BATCH_LOTs select new { p.SNO, p.BATCHNO, p.JOBNO, p.LOTNO, p.MODIFIEDDATE }).Distinct().Take(10);

        GridView1.DataSource = query;

        GridView1.DataBind();
    }

Updating the Row :

C#

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
       
LinqDataContext ld = new LinqDataContext();
        int Sno = Convert.ToInt32((GridView1.Rows[e.RowIndex].FindControl("lblSno") as Label).Text);
        if (Sno == 0)
        {
            return;
        }
        var result = (from x in ld.BATCH_LOTs where x.SNO  == Sno select x).FirstOrDefault();
        result.BATCHNO  = (GridView1.Rows[e.RowIndex].FindControl("txtBatch") as TextBox).Text;
        result.JOBNO = (GridView1.Rows[e.RowIndex].FindControl("txtJobNo") as TextBox).Text;
        result.LOTNO = (GridView1.Rows[e.RowIndex].FindControl("txtLotNo") as TextBox).Text;
        result.MODIFIEDDATE = (GridView1.Rows[e.RowIndex].FindControl("txtModifiedDate") as TextBox).Text;
       ld.SubmitChanges();
        GridView1.EditIndex = -1;
        binddata();

   }

Deleting the Row of Gridview :

C#

protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        LinqDataContext ld = new LinqDataContext();

        //Label sno = (Label)GridView1.Rows[e.RowIndex].FindControl("SNO");

        //int x1 = Convert.ToInt32(sno);

        string favoritesId = GridView1.Rows[e.RowIndex].Cells[0].Text;

        var delQuery =  from del in ld.BATCH_LOTs where del.SNO ==Convert.ToInt32( favoritesId) select del ;

 foreach (var x in delQuery)
        {
            ld.BATCH_LOTs.DeleteOnSubmit(x);
        }


        try
        {
            ld.SubmitChanges();

        }
        catch
        {
        }
        binddata();
    }

I got the Errors in Updating and Deleting the Rows of Gridview.

Posted 22-Oct-12 19:17pm

CH Guravaiah

Updated 24-Oct-12 19:38pm

v4

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Comments

Rajesh Kariyavula 23-Oct-12 2:03am

What is the error that occurred on update and delete?

CH Guravaiah 23-Oct-12 2:06am

In Update : Object reference not set to an instance of an object.

in Delete : Input string was not in a correct format.

Rajesh Kariyavula 23-Oct-12 2:16am

In delete where exactly you are getting the error.

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TanvirRaihan · Answer 1 · 2012-10-22T20:42:00

hi
Update:
--------------
ID of label control that holds SNO is... "lblSno"
So change the code from...

int Sno = Convert.ToInt32((GridView1.Rows[e.RowIndex].FindControl("SNO") as Label).Text);

to

int Sno = Convert.ToInt32((GridView1.Rows[e.RowIndex].FindControl("lblSno") as Label).Text);

better code will be..

C#

int Sno = 0 ;
Label lblSno = GridView1.Rows[e.RowIndex].FindControl("lblSno") as Label
if (lblSno != null)
{
    int.TryParse(lblSno.Text, out Sno);
}

This way you can prevent error.

For Delete
---------------------

I think your cell index (i.e

Cells[0]

) is not right. plesae check the following line

Hope this will help you

string favoritesId = GridView1.Rows[e.RowIndex].Cells[0].Text;