Simple Login Form in Windows Forms (WinForms) Application using C# and VB.Net

Here I have created sample for you that takes Username and Password and Match that credential in database if entered credential is valid then user will logged into the system else he/she will get appropriate error message.

I hope this will help you out.

C#.Net

Namespaces

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

C#

private void btnLogin_Click(object sender, EventArgs e)
{
    int count;
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand("SELECT COUNT(*) FROM Login WHERE UserName = @Userame AND [Password] = @Password", con))
        {
            cmd.Parameters.AddWithValue("@Userame", this.txtUsername.Text.Trim());
            cmd.Parameters.AddWithValue("@Password", this.txtPassword.Text);
            con.Open();
            count = Convert.ToInt32(cmd.ExecuteScalar());
            con.Close();
            if (count > 0)
            {
                MessageBox.Show("You have successfully Logged in");
            }
            else
            {
                MessageBox.Show(" Invalid Username or Password");
                this.txtPassword.Text = "";
                this.txtUsername.Focus();
            }
        }
    }
}

VB.Net

Namespaces

Imports System.Configuration
Imports System.Data.SqlClient

VB

Private Sub btnLogin_Click(sender As System.Object, e As System.EventArgs) Handles btnLogin.Click
    Dim count As Integer
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As New SqlConnection(constr)
        Using cmd As New SqlCommand("SELECT COUNT(*) FROM Login WHERE UserName = @Userame AND [Password] = @Password", con)
            cmd.Parameters.AddWithValue("@Userame", Me.txtUsername.Text.Trim())
            cmd.Parameters.AddWithValue("@Password", Me.txtPassword.Text)
            con.Open()
            count = Convert.ToInt32(cmd.ExecuteScalar())
            con.Close()
            If count > 0 Then
                MessageBox.Show("You have successfully Logged in")
            Else
                MessageBox.Show(" Invalid Username or Password")
                Me.txtPassword.Text = ""
                Me.txtUsername.Focus()
            End If
        End Using
    End Using
End Sub

Scrrenshot