how to change textbox.text from one child form to other child form. Both are open in MDI form in C#.net

Question

I have one MDI Form, With two Child Form named MDIParent1,Form1,Form2. MDI will Load with showing/loading this two child form in it.

private void MDIParent1_Load(object sender, EventArgs e)

    {
        Form childForm1 = new Form1();
        childForm1.MdiParent = this;
        childForm1.Show();

        Form childForm2 = new Form2();
        childForm2.MdiParent = this;
        childForm2.Show();
    }

In Form1 there is a textbox1 and a Button. And in form2 there is textbox2. So what i am trying to is when I write sometext in Form1's Textbox1 and then Click on Form1's Button, That same text will be write in Form2's Textbox2.

I Tried a lot. But Dosnt get output. the values are passing through one child form to other. but Textbox.text property is not updating.

I tried it Without MDI Form. The Form1 And Form2 will opened independently. and I have to close and reopen Form2 each and every time when i click on Form1's Button. It Works little bit. But I need it in MDI Form. While Both Child Forms were opened in MDI and then I want to Update property of textbox (In short I need to do this form2.textbox.text = Form1.textbox.text where Form1 and Form2 both are Child forms)

Regards, Salil

How does your code look like to set the text of textbox2 on form2? Have you tried refreshing the form? — surfmuggle, Jun 23 '13 at 09:13

score 0 · Accepted Answer · answered Jun 23 '13 at 10:51

Try using the the MDI parent (MDIParent1) as a moderator between the 2 forms.
MDIParent1 will register to Form1's events and will modify Form2 respectively.

Modifications for Form1

Add to Form1 a public event notifying that the button was pressed. The event should also contain information about the current text in textBox1. For this, use a class deriving from EventArgs:

The EventArgs:

public class TextChangedArgs:EventArgs
{
    string _text;

    /// <summary>
    /// Gets text .
    /// </summary>
    /// <value>
    /// The text.
    /// </value>
    public string Text
    {
        get { return _text; }
    }

    public TextChangedArgs(string text)
    {
        this._text = text;
    }
}

The Public Event:

public event EventHandler<TextChangedArgs> OnTextChanged;

The Button1 Click Event:

 private void button1_Click(object sender, EventArgs e)
    {
        if (this.OnTextChanged != null)
        {
            this.OnTextChanged(this, new TextChangedArgs(this.textBox1.Text));
        }
    }

Modification to MDIParent1

In the following code, the modification is the registration to the event, and handling it:

 void MDIParent1_Load(object sender, EventArgs e)
    {
        Form1 childForm1 = new Form1();
        childForm1.MdiParent = this;
        childForm1.OnTextChanged += childForm1_OnTextChanged;
        childForm1.Show();

        Form2 childForm2 = new Form2();
        childForm2.MdiParent = this;
        childForm2.Show();
    }

    void childForm1_OnTextChanged(object sender, TextChangedArgs e)
    {
        //just getting the Form 2 instance, you can implement it in any way you choose to (e.g. make it global...)
        Form2 childForm2 = this.MdiChildren.Where(c => c is Form2).FirstOrDefault() as Form2;
        if (childForm2 != null)
        {
            childForm2.SetText(e.Text);
        }

    }

Modifications to Form2

The modification is Adding a public method for setting the text:

 public void SetText(string text)
    {
        this.textbox2.Text = text;
    }

this should work for you...

@user2367130 .. if this answer helps you then you have to make a geen check below the downvote sign (accept this as the answer) .. — matzone, Jun 23 '13 at 13:20

how to change textbox.text from one child form to other child form. Both are open in MDI form in C#.net

1 Answers1

Modifications for Form1

Modification to MDIParent1

Modifications to Form2