Could Any One tell Me what is the wrong in this C# code .... And It Is Code for Delete Mutliple records In Data List control and also i place this source code also,,,,

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Source code:

ASP.NET

<Table border="3" align="Center">
      <asp:DataList ID="DataList1" runat="server">
          <HeaderTemplate>
              <tr>
                  <th><asp:CheckBox ID="ChkAll" runat="server" /></th>
                  <th>EmpId</th><th>EName</th><th>Designation</th><th>DOJ</th><th>Salary</th><th>Deptno</th>
              </tr>
          </HeaderTemplate>
          <ItemTemplate>
              <tr>
                  <th><asp:CheckBox ID="ChkOne" runat="server" /></th>
                  <th><asp:Label ID="lblEmpId" runat="server" Text='<%#Eval("EmpId") %>'></asp:Label></th>
                  <th><%#Eval("EName") %></th>
                  <th><%#Eval("Designation") %></th>
                  <th><%#Eval("DOJ") %></th>
                  <th><%#Eval("Salary") %></th>
                  <th><%#Eval("Deptno") %></th>
              </tr>
          </ItemTemplate>

      </asp:DataList>
  </Table>

C# Code:

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;

public partial class DeleteMultipleRecordsUsingDataListControl : System.Web.UI.Page
{
    SqlConnection con = new SqlConnection("server=Dexter;User Id=sa;Password=123;Database=Vishnu");
    protected void Page_Load(object sender, EventArgs e)
    {
        if (Page.IsPostBack == false)
            GetData();
    }
    private void GetData()
    {
        SqlDataAdapter Da = new SqlDataAdapter("select*from EmpDetails", con);
        DataSet Ds = new DataSet();
        Da.Fill(Ds, "X");
        DataList1.DataSource = Ds.Tables[0];
        DataList1.DataBind();
    }
    protected void btnDelete_Click(object sender, EventArgs e)
    {
        con.Open();
        foreach(DataListItem L in DataList1.Items)
        {
            CheckBox C1 = (CheckBox)L.FindControl("ChkOne");
            if (C1.Checked == true)
            {
                Label L1 = (Label)L.FindControl("lblEmpId");
                string s = "Delete EmpDetails Where EmpId=" + L1.Text;
                SqlCommand cmd = new SqlCommand(s, con);
                cmd.ExecuteNonQuery();
            }
            con.Close();
            GetData();
        }
    }
}

And I am Getting Runtime Error Like this [Collection was modified; enumeration operation may not execute.]

Posted 27-Feb-13 6:42am

Dwijender

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3 solutions

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vishal.shimpi · Answer 1 · 2013-02-27T18:36:00

Use following code...

protected void btnDelete_Click(object sender, EventArgs e)
    {
        List<string> tempEmpID = new List<string>();
        con.Open();
        foreach(DataListItem L in DataList1.Items)
        {
            CheckBox C1 = (CheckBox)L.FindControl("ChkOne");
            if (C1.Checked == true)
            {
                Label L1 = (Label)L.FindControl("lblEmpId");
                tempEmpID.add(L1.Text);
            }
                      
        }
        Foreach(string str in tempEmpID)
        {
           if(con.ConnectionState == ConnectionState.Close)
               con.Open();
           string s = "Delete EmpDetails Where EmpId=" + L1.Text;
           SqlCommand cmd = new SqlCommand(s, con);
           cmd.ExecuteNonQuery();
                      
        } 
        con.Close();
        GetData();
    }</string></string>

sistec · Answer 2 · 2013-02-27T07:10:00

basically you can't modify an enumeration (for each) like adding or deleting items while you are looping, that is because if you are in the middle of the loop and some items got removed when ever you get to the next item it might already been removed, you need to modify your logic here and probably use a FOR loop instead of a FOREACH: something like this:

C#

for (int i = list.Count - 1; i >= 0; i--)
{
    if (true)
    	list.RemoveAt(i);
}

and I believe that Lists do support Reverse traversing (not sure) but the key is to do it backwards as shown using the for loop

bbirajdar · Answer 3 · 2013-02-27T07:10:00

Solution 1

You should not delete the the items from the collection you are iterating.

C#

foreach(DataListItem L in DataList1.Items)
       {

Instead you should first create the list of checked items .
Then delete them from database.
Then fire the select query and then bind .

This way a select query will also be fired only once , even for multiple deletes.

Posted 27-Feb-13 7:10am

bbirajdar

Updated 27-Feb-13 7:12am

v2

Comments

Dwijender 27-Feb-13 13:17pm

i am selecting the record at the execution time then why would i write instead of this foreach loop???

Dwijender 27-Feb-13 13:22pm

Could you post me the Code for Delete button ???

bbirajdar 28-Feb-13 10:39am

You write the code according to the steps I have mentioned and if anything goes wrong, I will correct it...Your company pays you for writing the code..Not me

Could Any One tell Me what is the wrong in this C# code .... And It Is Code for Delete Mutliple records In Data List control and also i place this source code also,,,,

3 solutions

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