Calling a method from another form

Question

Hey I have a windows form and im trying to call a method from another form but im struggling because i keep getting the error code: An object reference is required for the nonstatic field method or property 'ShutdownTimer.Form1.richTextBox1()' The following is the code ive used. Form2 ***** private void close_Click(object sender EventArgs e) { Form1.update(); //this.Close(); } Form1 ***** public static void update() { richTextBox1.Text = Updated + 
; } I thought i got round the error code by using the following code. Form2 ***** private void close_Click(object sender EventArgs e) { Form1.update(); //this.Close(); } Form1 ***** public static void update() { Form1 fm = new Form1(); fm.richTextBox1.Text = Updated + 
; } So this compiles but “Updated” doesn’t appear in the richTextBox. What have i done wrong? Hope to hear a response soon Rob · EDIT: In the code above i added a button on to Form2 to call method asd. Even that wasnt able to put qwerty in to the richTextBox1. Let alone trying to call it from another method. I have made a new project now so i could figure this out. I dont want to mess around too much with the proper program. Thats why the method names have changed. I now have the following code. Form1 ***** public void button2_Click(object sender EventArgs e) { Form2 fm = new Form2(); fm.asd(); } Form2 ***** public void asd() { i += 1; MessageBox.Show(here  + i asd); this.richTextBox1.Text += qwerty  + i + 
; } From Form1 the method asd is called and i get the messageBox but qwerty isnt wrote in to richTextBox1. i is also updated every time i call it from Form1. If i click the button on Form2 that calls asd it works perfectly. So what am i now missing out for the richTextBox1 to work properly? I have noticed other things to do with the objects on the form like buttons to not show and hide when the method is called from Form1. Hope to hear a response soon

Satish Kathi · Answer

Here is the code In Form1 declare form2 variable at class level public partial class Form1 : Form { Form2 f; rest of the forms code........ } Button click in the Form1 private void button2_Click( object sender EventArgs e) { if (f == null ) f = new Form2 (); f.asd(); f.Show(); } In Form2 asd method code public void asd() { i += 1; MessageBox .Show( here  + i asd ); this .richTextBox1.Text += qwerty  + i + 
 ; }

Alan · Answer

To be able to change an instance property of a form from another form the second form needs to have a reference to the first form's instance. There are various ways of obtaining this but if you have .NET 2.0 or later then one way that always works is to use the Application.OpenForms property. For example: // code on Form2 Form1 f1 = (Form1)Application.OpenForms[Form1]; f1.Opacity = 0.75; // say f1.Visible = true; //if necessary

Rob · Answer

I dont want to do it that way. I want to do it as a function of my program. So i want one form to be able to hide/show or turn the opacity of another form up and down.

Ryan Alford · Answer

in the designer view click on the form open the properties window then change the Opacity property.

Rob · Answer

I thought i would add this question on to this form since its to do with the same thing. How can i change the opacity of another form? I have a main form now ive added a disclaimer that pop ups before the main screen appears. The main form must load first and hide itself before the disclaimer appears.

Rob · Answer

Cheers. I implemented your example to work in my program and it worked nicely.

Ryan Alford · Answer

this code works fine: ----- Form1 --------- public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button1_Click(object sender EventArgs e) { Form2 f2 = new Form2(); f2.Update(); f2.Show(); } } ----- Form2 --------- public partial class Form2 : Form { public Form2() { InitializeComponent(); } public void Update() { RichTextBox rtb = new RichTextBox(); rtb.Location = new Point(86 76); rtb.Text = Updated; this.Controls.Add(rtb); } }

Rob · Answer

Ive done that havnt i? If not then how do i alter it? Im only a rookie when it comes to programming in C#

Ryan Alford · Answer

you want the RichTextBox to be PUBLIC. if it's PRIVATE you can't modify it outside of it's class(Form).

Rob · Answer

I think ive changed the modifiers.The richTextBox1 is in form2. So I went into Form2.Designer.cs and i changed the line private System.Windows.Forms. RichTextBox richTextBox1; to public System.Windows.Forms. RichTextBox richTextBox1; Im using visual studio. The text still doesnt appear in the richTextBox1. Its working exactly the same after my second attempt. EDIT: If i stick in this line MessageBox.Show(frm.richTextBox1.Text); like Techy Wizard suggested. The message box displays what i want the richTextBox to display even though its not displaying it.

Satish Kathi · Answer

You are getting error object reference because you are calling an instance member in a static method. Form1 ***** public static void update() { richTextBox1.Text = Updated + 
; } Method update is a static method where as richTextBox1 is an instance member hence it is throwing error. And in your second attempt set the Modifiers property of the RichTextBox to Public and when you are calling the “asd” method pass the Form1 as a parameter and update the richTextBox of this parameter and you can see the output in Form1’s richText Box. Here is code Form2 public void asd( Form1 frm) { i += 1; MessageBox .Show( here  + i asd ); //this.richTextBox1.Text += qwerty  + i + 
; frm.richTextBox1.Text += qwerty  + i + 
 ; } Form1 private void button2_Click( object sender EventArgs e) { Form2 f = new Form2 (); f.asd( this ); }

Techy Wizard · Answer

As far as I understand your question You have one form Form1 which contains a rich text box. There is a method update which sets some text for the rich text box. You have another form Form2 which has a button. And on the button click you want to call the method update (present in Form1) to set the text of the rich text box. Try this: In Form2: // Declare the update method as an instance method public void update() { richTextBox1.Text = Updated; } In Form2: private void btnClose_Click(object sender EventArgs e) { Form1 frm = new Form1(); frm.update(); } This will work absolutely fine. To verify whether the rich text box has been updated add this line of code to the click of the button after making the call to the update() method: MessageBox.Show(frm.richTextBox1.Text); However for that first you need to change the access specifier of the richtext box from private to public. Hope this helps.