passing data between 3 windows forms in visual studio using C#

Question

I have a windows application which has 3 forms : Form1,2,3. I want to send text of a textbox from form2 to form1 and then that same text from for

Answer 1

That error is thrown because Form3 has no default Constructor anymore since you defined one with a string parameter. you need to create a default Constructor like this public Form3(){}.

But Instead of doing all this mess you can handle events of you both forms. Like if Form1 is the main Form then something like this can be done:

In Form1

public string textFromForm2 = string.Empty;
private void openform3_Click(object sender, EventArgs e)
{
    Form3 f3 = new Form3();
    f3.Controls["received_from_form1_textbox"].Text = textFromForm2 ;
    f3.Show();
}

private void OPENFORM2_Click(object sender, EventArgs e)
{
    Form2 f2 = new Form2();
    //I am binding the event to a handler which will save text
    //you should check for null for f2.Controls returned any thing or not, i am leaving it for now
    f2.Controls["send_to_form1_button"].Click += (s,e)=>{
                 txtFromForm2 = f2.Controls["form2_textbox"].Text;
          };
    f2.Show();
}

Update

if you don't want to use Lambadas then bind events like this:

First you will need a reference to the Form2 so declare in your class like this:

Form2 f2;

then bind the event (in place of the lambada i have given before)

f2.Controls["send_to_form1_button"].Click  += new Eventhandler(click_handler);

then somewhere in Form1 class:

protected void click_handler(object sender, EventArgs e)
{
     if(f2 != null)
         txtFromForm2 = f2.Controls["form2_textbox"].Text;
}

similarly for Form3.