Question

I have an issue regarding Sendkeys Class, as i want to use this class in order to send some keystroke to the active application.
As a first step i want to test the {Enter} keystroke, so in order to achieve that i made a simple application in vb.net 2010

Public Class Form1
Public Shared data As String
Private Sub SendintText(command As String)
    Try
        SendKeys.SendWait(command)
    Catch e As Exception
        MsgBox(e.StackTrace)
    End Try
End Sub

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    data = TextBox1.Text.ToString
    SendingText(data)
End Sub

End Class

When i tried to run for {Enter} i have received infinit loop error:
An unhandled exception of type ‘System.StackOverflowException’ occurred in System.Windows.Forms.dll
Could someone help me?

LATER EDIT : In meantime i have found another example

Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    System.Threading.Thread.Sleep(2000)
    SendKeys.SendWait("{ENTER}")
End Sub

If in background i have two applications :

1. Visual Studio
2. Target application

How can i focus on the target application, because now when i am running the form , that form became active..is there any solution to call the winform from command prompt with some parameter (the key that i want to send)?

Later Edit2
strong text
i have give it up the idea for windows form, so finnally i have made a simple program in console application that simulates the keystroke … Imports System
Imports System.Windows.Forms

Module Module1

Sub Main(ByVal args() As String)
    Dim data As String = args(0)
    Console.WriteLine("You insert the : {0}", data)
    System.Threading.Thread.Sleep(5000)
    SendKeys.SendWait(data)
End Sub

End Module

By the way in order to use double quotes in a parameter you need \”test\”…(i have spent 15 min to find out) so it might be usefull…
Thanks again for the informations.

Answer 1

In order to sendkey to another application, you need to first activate that application on the button click and then send keys

MSDN Link

// Get a handle to an application window.
[DllImport("USER32.DLL", CharSet = CharSet.Unicode)]
public static extern IntPtr FindWindow(string lpClassName,
    string lpWindowName);

// Activate an application window.
[DllImport("USER32.DLL")]
public static extern bool SetForegroundWindow(IntPtr hWnd);

// Send a series of key presses to the Calculator application.
private void button1_Click(object sender, EventArgs e)
{
    // Get a handle to the Calculator application. The window class
    // and window name were obtained using the Spy++ tool.
    IntPtr calculatorHandle = FindWindow("CalcFrame","Calculator");

    // Verify that Calculator is a running process.
    if (calculatorHandle == IntPtr.Zero)
    {
        MessageBox.Show("Calculator is not running.");
        return;
    }

    // Make Calculator the foreground application and send it 
    // a set of calculations.
    SetForegroundWindow(calculatorHandle);
    SendKeys.SendWait("111");
    SendKeys.SendWait("*");
    SendKeys.SendWait("11");
    SendKeys.SendWait("=");
}