Delete multiple records from gridview

Question

<asp:GridView EnableViewState="true" DataKeyNames="ID" style="width:100%;" ID="tableUsers" runat="server"  CssClass="table table-striped table-bordered" AllowSorting="True" AllowPaging="True" OnPageIndexChanging="tableUsers_PageIndexChanging" AutoGenerateDeleteButton="True" AutoGenerateEditButton="True" OnRowDeleting="tableUsers_RowDeleting" OnRowEditing="tableUsers_RowEditing" AutoGenerateColumns="False" OnRowCancelingEdit="tableUsers_RowCancelingEdit" OnRowUpdating="tableUsers_RowUpdating" OnSorting="tableUsers_Sorting">
                                        <Columns>
                                            <asp:TemplateField HeaderText="ID" Visible="False">
                                                <ItemTemplate>
                                                    <asp:Label ID="txtID" runat="server" Text='<%# Eval("ID") %>'></asp:Label>
                                                </ItemTemplate>
                                            </asp:TemplateField>
                                            <asp:TemplateField HeaderText="Username">
                                                <EditItemTemplate>
                                                    <asp:TextBox ID="txtUsername" runat="server" Text='<%# Eval("Username") %>'></asp:TextBox>
                                                </EditItemTemplate>
                                                <ItemTemplate>
                                                    <asp:Label ID="Label1" runat="server" Text='<%# Eval("Username") %>'></asp:Label>
                                                </ItemTemplate>
                                            </asp:TemplateField>
                                            <asp:TemplateField>
                                              <ItemTemplate>
                                                <asp:CheckBox ID="deleteBox" runat="server" Enabled="true"/>
                                              </ItemTemplate>
                                           </asp:TemplateField>

                                        </Columns>

                                    </asp:GridView>
 protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
           tableFill();
        }

    }
protected void Button2_Click(object sender, EventArgs e)
    {
        try
        {
            bool checkedfound = false;
            foreach (GridViewRow grow in tableUsers.Rows)
            {
                //Searching CheckBox("chkDel") in an individual row of Grid  
                CheckBox chkBx = (CheckBox)grow.FindControl("deleteBox");
                //If CheckBox is checked than delete the record with particular empid  
                if (chkBx != null && chkBx.Checked)
                {
                    string id = tableUsers.DataKeys[grow.RowIndex].Values["ID"].ToString();
                    master.execute("DELETE FROM Users WHERE ID='" + id + "'", "User Deleted", "ERROR");
                    checkedfound = true;
                }
            }  

            if(checkedfound){
                alert("Selected users deleted", true);
                tableFill();
            }
            else
            {
                alert("no checks found",false);
            }
        }
        catch (Exception x)
        {
            alert("Delete Fail: "+x.ToString(), false);
        }
    }
protected void tableUsers_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        try
        {
            string id = tableUsers.DataKeys[e.RowIndex].Values["ID"].ToString();
            master.execute("DELETE FROM Users WHERE ID='" + id + "'", "User Deleted", "ERROR");
            alert("User deleted",true);
            tableFill();
        }
        catch (Exception)
        {
            alert("Delete Failed",false);
        }
    }
 private void tableFill()
    {
        string constr = System.Configuration.ConfigurationManager.ConnectionStrings["WebAppConnString"].ToString();
        using (MySqlConnection con = new MySqlConnection(constr))
        {
            using (MySqlCommand cmd = new MySqlCommand("SELECT ID,Username,Email,Rank,IP FROM Users"))
            {
                using (MySqlDataAdapter sda = new MySqlDataAdapter())
                {
                    cmd.Connection = con;
                    sda.SelectCommand = cmd;
                    using (DataTable dt = new DataTable())
                    {
                        sda.Fill(dt);
                        tableUsers.DataSource = dt;
                        tableUsers.DataBind();
                    }
                }
            }
        }


    }

Trying to delete multiple rows upon Buttob2 click. However, i keep recieving the error of "no checks found". Ive tried adding the !postback in the load but still no luck. I have also coppied others code on the same issue and the only responses are to add the !postback

(The gridview loads the data fine and tableUsers_RowDeleting works)

Answer 1

If I understand your issue, you would like to select multiple rows at once and delete those record on single button click.

Could you attempt this code:

This way you may exclude using separate row deleting event and you may not need to keep EnableViewState property.

protected void btnDelete_Click(object sender, EventArgs e)   
{   
     foreach (GridViewRow row in GridViewEmployee.Rows)   
        {   
          if ((row.FindControl("chkSelect") as CheckBox).Checked)   
          {   
               int recordid = Convert.ToInt32(gridview.DataKeys[row.RowIndex].Value);   
               using (SqlConnection con = new SqlConnection(@"Data Source=mssql; Initial Catalog=dbname; Uid=sa; pwd=sa;"))   
               {   
                   con.Open();   
                   SqlCommand cmd = new SqlCommand("DELETE FROM `[table]` WHERE ID=" + recordid, con);   
                   cmd.ExecuteNonQuery();   
                   con.Close();   
               }   
           }   
       }
    BindGrid();   
}

I hope this helps or gives some insight.

UPDATE:

List<int> list = new List<int>(); 
    if (ViewState["SelectedRecords"] != null) 
    { 
        list = (List<int>)ViewState["SelectedRecords"]; 
    } 
    foreach (GridViewRow row in GridView1.Rows) 
    { 
        CheckBox chk = (CheckBox)row.FindControl("chkSelect"); 
        var selectedKey = 
        int.Parse(GridView1.DataKeys[row.RowIndex].Value.ToString()); 
        if (chk.Checked) 
        { 
            if (!list.Contains(selectedKey)) 
            { 
                list.Add(selectedKey); 
            } 
        } 
        else 
        { 
            if (list.Contains(selectedKey)) 
            { 
                list.Remove(selectedKey); 
            } 
        } 
    } 
    ViewState["SelectedRecords"] = list; 
    //BindGrid(); 
}