Check if record already exists in Database in Windows Application

Hi haider6.9,

Please refer below sample.

Namespaces

C#

using System.Data.SqlClient;

VB.Net

Imports System.Data.SqlClient

Code

C#

private void button1_Click(object sender, EventArgs e)
{
    SqlConnection con = new SqlConnection("Server=.;DataBase=Test;UID=sa;PWD=pass@123");
    SqlCommand cmd = new SqlCommand("SELECT * FROM Customers WHERE Name=@Name", con);
    cmd.Parameters.AddWithValue("@Name", txtName.Text.ToLower());
    con.Open();
    SqlDataReader dr = cmd.ExecuteReader();
    if (dr.HasRows)
    {
        MessageBox.Show("Record already exist");
        con.Close();
    }
    else
    {
        con.Close();
        con.Open();
        cmd = new SqlCommand("Insert INTO Customers(Name,Country) VALUES(@name,@Country)", con);
        cmd.Parameters.AddWithValue("@name", txtName.Text);
        cmd.Parameters.AddWithValue("@Country", txtCountry.Text);
        cmd.ExecuteNonQuery();
        con.Close();
        MessageBox.Show("Record Inserted Successfully.");
    }
}

VB.Net

Private Sub button1_Click(sender As System.Object, e As System.EventArgs) Handles button1.Click
    Dim con As SqlConnection = New SqlConnection("Server=.;DataBase=Test;UID=sa;PWD=pass@123")
    Dim cmd As SqlCommand = New SqlCommand("SELECT * FROM Customers WHERE Name=@Name", con)
    cmd.Parameters.AddWithValue("@Name", txtName.Text.ToLower())
    con.Open()
    Dim dr As SqlDataReader = cmd.ExecuteReader()

    If dr.HasRows Then
        MessageBox.Show("Record already exist")
        con.Close()
    Else
        con.Close()
        con.Open()
        cmd = New SqlCommand("Insert INTO Customers(Name,Country) VALUES(@name,@Country)", con)
        cmd.Parameters.AddWithValue("@name", txtName.Text)
        cmd.Parameters.AddWithValue("@Country", txtCountry.Text)
        cmd.ExecuteNonQuery()
        con.Close()
        MessageBox.Show("Record Inserted Successfully.")
    End If
End Sub

Screenshot