Compare ASP.Net GridView row count with DropDownList selected value usiing C# and VB.Net

Hi akhter,

I have created a sample please take its reference.

Database

For this example I have used of Northwind database that you can download using the link given below.

Download Northwind Database

HTML

Name : <asp:TextBox ID="txtName" runat="server" /><br />
City : <asp:TextBox ID="txtCity" runat="server" /><br />
Country : <asp:TextBox ID="txtCountry" runat="server" /><br />
<asp:DropDownList runat="server" ID="ddlNumber">
    <asp:ListItem Value="--Select--" Text="--Select--" />
    <asp:ListItem Value="1" Text="1" />
    <asp:ListItem Value="4" Text="4" />
    <asp:ListItem Value="9" Text="9" />
</asp:DropDownList><br /><br />
<asp:Button Text="Insert" runat="server" ID="btnInsert" OnClick="OnInsert" /><br /><br />
<asp:GridView runat="server" ID="gvCustomers" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="CustomerID" HeaderText="ID" />
        <asp:BoundField DataField="ContactName" HeaderText="Name" />
        <asp:BoundField DataField="City" HeaderText="City" />
        <asp:BoundField DataField="Country" HeaderText="Country" />
    </Columns>
</asp:GridView>

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 (!this.IsPostBack)
    {
        this.BindCustomers();
    }
}

private void BindCustomers()
{
    using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString))
    {
        using (SqlCommand cmd = new SqlCommand("SELECT CustomerID,ContactName,City,Country FROM Customers", con))
        {
            cmd.CommandType = CommandType.Text;
            using (SqlDataAdapter sda = new SqlDataAdapter())
            {
                sda.SelectCommand = cmd;
                DataTable dt = new DataTable();
                sda.Fill(dt);
                this.gvCustomers.DataSource = dt;
                this.gvCustomers.DataBind();
            }
        }
    }
}

protected void OnInsert(object sender, EventArgs e)
{
    int number = Convert.ToInt32(ddlNumber.SelectedValue);
    gvCustomers.AllowPaging = false;
    BindCustomers();
    int rowCount = gvCustomers.Rows.Count;
    gvCustomers.AllowPaging = true;
    BindCustomers();
    if (number < rowCount)
    {
        string name = txtName.Text;
        string city = txtCity.Text;
        string country = txtCountry.Text;
        this.Insert(name, city, country);
    }
}

private void Insert(string name, string city, string country)
{
    using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString))
    {
        using (SqlCommand cmd = new SqlCommand("INSERT INTO tblCustomers VALUES(Name,City,Country)", con))
        {
            cmd.CommandType = CommandType.Text;
            cmd.Parameters.AddWithValue("@Name", name);
            cmd.Parameters.AddWithValue("@City", city);
            cmd.Parameters.AddWithValue("@City", country);
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
        }
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Me.BindCustomers()
    End If
End Sub

Private Sub BindCustomers()
    Using con As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString)
        Using cmd As SqlCommand = New SqlCommand("SELECT CustomerID,ContactName,City,Country FROM Customers", con)
            cmd.CommandType = CommandType.Text
            Using sda As SqlDataAdapter = New SqlDataAdapter()
                sda.SelectCommand = cmd
                Dim dt As DataTable = New DataTable()
                sda.Fill(dt)
                Me.gvCustomers.DataSource = dt
                Me.gvCustomers.DataBind()
            End Using
        End Using
    End Using
End Sub

Protected Sub OnInsert(ByVal sender As Object, ByVal e As EventArgs)
    Dim number As Integer = Convert.ToInt32(ddlNumber.SelectedValue)
    gvCustomers.AllowPaging = False
    BindCustomers()
    Dim rowCount As Integer = gvCustomers.Rows.Count
    gvCustomers.AllowPaging = True
    BindCustomers()
    If number < rowCount Then
        Dim name As String = txtName.Text
        Dim city As String = txtCity.Text
        Dim country As String = txtCountry.Text
        Me.Insert(name, city, country)
    End If
End Sub

Private Sub Insert(ByVal name As String, ByVal city As String, ByVal country As String)
    Using con As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString)
        Using cmd As SqlCommand = New SqlCommand("INSERT INTO tblCustomers VALUES(Name,City,Country)", con)
            cmd.CommandType = CommandType.Text
            cmd.Parameters.AddWithValue("@Name", name)
            cmd.Parameters.AddWithValue("@City", city)
            cmd.Parameters.AddWithValue("@City", country)
            con.Open()
            cmd.ExecuteNonQuery()
            con.Close()
        End Using
    End Using
End Sub