Delete row from GridView and ViewState using C# and VB.Net in ASP.Net

Hi akhter,

Check the exmple.

HTML

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" DataKeyNames="CustomerId" OnRowDeleting="GridView1_RowDeleting">
    <Columns>
        <asp:BoundField DataField="CustomerId" HeaderText="Id" />
        <asp:BoundField DataField="Name" HeaderText="Name" />
        <asp:BoundField DataField="Country" HeaderText="Country" />
        <asp:CommandField ButtonType="Button" ShowDeleteButton="True" />
    </Columns>
</asp:GridView>
<hr />
ID:<asp:TextBox runat="server" ID="txtID" />
<br />
Name:<asp:TextBox runat="server" ID="txtName" />
<br />
Country:<asp:TextBox runat="server" ID="txtCountry" />
<br />
<asp:Button ID="btnAdd" runat="server" Text="Add" OnClick="OnAdd" />

Namespaces

C#

using System.Configuration;
using System.Data;
using System.Data.SqlClient;

VB.Net

Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        PopulateData();
        BindGridView();
    }
}
protected void OnAdd(object sender, EventArgs e)
{
    DataTable dtgridview = ViewState["Data"] as DataTable;
    DataRow dr2 = dtgridview.NewRow();
    dr2["CustomerId"] = txtID.Text;
    dr2["Name"] = txtName.Text;
    dr2["Country"] = txtCountry.Text;
    dtgridview.Rows.Add(dr2);
    ViewState["Data"] = dtgridview;
    BindGridView();
}
protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
    DataTable dt = (DataTable)ViewState["Data"];
    int index = Convert.ToInt32(e.RowIndex);
    // Delete from ViewState.
    dt.Rows[index].Delete();
    ViewState["Data"] = dt;
    if (GridView1.DataKeys[e.RowIndex].Value != DBNull.Value)
    {
        int id = Convert.ToInt32(GridView1.DataKeys[index].Value);
        // Delete from Database.
        string constr = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constr))
        {
            string query = "DELETE FROM Customers WHERE CustomerId = @Id";
            using (SqlCommand cmd = new SqlCommand(query))
            {
                cmd.Connection = con;
                cmd.Parameters.AddWithValue("@Id", id);
                con.Open();
                cmd.ExecuteNonQuery();
                con.Close();
            }
        }
    }
    BindGridView();
}
private void BindGridView()
{
    GridView1.DataSource = ViewState["Data"] as DataTable;
    GridView1.DataBind();
}
private void PopulateData()
{
    string constr = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        string query = "SELECT * FROM Customers";
        using (SqlCommand cmd = new SqlCommand(query))
        {
            cmd.Connection = con;
            SqlDataAdapter sda = new SqlDataAdapter(cmd);
            DataTable dt = new DataTable();
            sda.Fill(dt);
            ViewState["Data"] = dt;
        }
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not IsPostBack Then
        PopulateData()
        BindGridView()
    End If
End Sub
Protected Sub OnAdd(ByVal sender As Object, ByVal e As EventArgs)
    Dim dtgridview As DataTable = TryCast(ViewState("Data"), DataTable)
    Dim dr2 As DataRow = dtgridview.NewRow()
    dr2("CustomerId") = txtID.Text
    dr2("Name") = txtName.Text
    dr2("Country") = txtCountry.Text
    dtgridview.Rows.Add(dr2)
    ViewState("Data") = dtgridview
    BindGridView()
End Sub
Protected Sub GridView1_RowDeleting(ByVal sender As Object, ByVal e As GridViewDeleteEventArgs)
    Dim dt As DataTable = CType(ViewState("Data"), DataTable)
    Dim index As Integer = Convert.ToInt32(e.RowIndex)
    ' Delete from ViewState.
    dt.Rows(index).Delete()
    ViewState("Data") = dt
    If Not IsDBNull(GridView1.DataKeys(e.RowIndex).Value) Then
        Dim id As Integer = Convert.ToInt32(GridView1.DataKeys(e.RowIndex).Value)
        ' Delete from Database.
        Dim constr As String = ConfigurationManager.ConnectionStrings("conString").ConnectionString
        Using con As SqlConnection = New SqlConnection(constr)
            Dim query As String = "DELETE FROM Customers WHERE CustomerId = @Id"
            Using cmd As SqlCommand = New SqlCommand(query)
                cmd.Connection = con
                cmd.Parameters.AddWithValue("@Id", id)
                con.Open()
                cmd.ExecuteNonQuery()
                con.Close()
            End Using
        End Using
    End If
    BindGridView()
End Sub
Private Sub BindGridView()
    GridView1.DataSource = TryCast(ViewState("Data"), DataTable)
    GridView1.DataBind()
End Sub
Private Sub PopulateData()
    Dim constr As String = ConfigurationManager.ConnectionStrings("conString").ConnectionString
    Using con As SqlConnection = New SqlConnection(constr)
        Dim query As String = "SELECT * FROM Customers"
        Using cmd As SqlCommand = New SqlCommand(query)
            cmd.Connection = con
            Dim sda As SqlDataAdapter = New SqlDataAdapter(cmd)
            Dim dt As DataTable = New DataTable()
            sda.Fill(dt)
            ViewState("Data") = dt
        End Using
    End Using
End Sub

Screenshot