Public Class Form1
 Private Declare Function GetAsyncKeyState Lib "user32" (ByVal vkey As Long) As Integer

 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
 MsgBox("merhaba " & TextBox1.Text)
 End Sub


 Private Sub TextBox1_KeyDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyDown
 Dim enterebas As Boolean
 enterebas = GetAsyncKeyState(Keys.Return)
 If enterebas = True Then
 Button1_Click(sender, e)
 End If
 End Sub
End Class