How to read property of external form

Enc Rypt

Hello, well basically, i created a windows form application when i started my project and i have created two extra forms (options and about). The options tab has a few checkbox's like: minimize to tray and top-most program and in my main form i have the code:

 if (this.WindowState == FormWindowState.Minimized == true)
 {
     notifyIcon1.Visible = true;
     this.WindowState = FormWindowState.Minimized;
     this.ShowInTaskbar = false;
 }

but i want to do something like

 if (this.WindowState == FormWindowState.Minimized == true && Options.checkBox1.Checked == true)
 {
     notifyIcon1.Visible = true;
     this.WindowState = FormWindowState.Minimized;
     this.ShowInTaskbar = false;
 }

but i can't find a way to read the properties of the controls on form3(Options), i tried changing the controls in the designer code portion of the form from private to public, but still no success. I would really appreciate any help on this topic. Thanks in advance.

7 Replies

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Kirtan Patel17y ago

Accepted answer

Error is Because you have not Opened Options Form 

Below code will work if Option Form is Open 
so in form1's Load Event Write 

form1_load(Object Sender,EventArgs e)
{
Options f2 = new Options();
f2.Show
}

//then after this will work :)

 private void form1_Resize(object sender, EventArgs e)
 {
     Form f = Application.OpenForms["Options"];
     bool CheckBox1State = ((Options)f).checkBox1.Checked;
     if (this.WindowState == FormWindowState.Minimized == true && CheckBox1State == true)
     {
         notifyIcon1.Visible = true;
         this.WindowState = FormWindowState.Minimized;
         this.ShowInTaskbar = false;
     }
 }

If still need assistance let me know i will help you :)

and friend , please check "Do you like this answer" if my answer helped you :)

Enc Rypt17y ago
it's finally working :D thanks so much for all the help.
Enc Rypt17y ago
Thanks :) but now it's crashing with the error:
Additional information: Object reference not set to an instance of an object.
on the Form "f", i tried putting Form f = new form(); before the code and it didn't help. it shows the contents of f as "null"

Kirtan Patel17y ago

 private void form1_Resize(object sender, EventArgs e)
 {
     Form f = Application.OpenForms["Options"];
     bool CheckBox1State = ((Options)f).checkBox1.Checked;
     if (this.WindowState == FormWindowState.Minimized == true && CheckBox1State == true)
     {
         notifyIcon1.Visible = true;
         this.WindowState = FormWindowState.Minimized;
         this.ShowInTaskbar = false;
     }
 }

Here in Highlighted code  Use Your Option Form's Name Properties Value I used Options Because i Named Form Option :)

Serban Cosmin17y ago
Marking the control ( CheckBox ) as public in the form you've created is enough to access it. So, if you have the Options class with the public property checkBox1, and have : Options myOptions = new Options( ); , you should be able to call myOptions.checkBox1 without any other formalities. Make sure your classes share the same namespace or ar properly accessed across namespaces and that in your code the field is declared with a public modifier, regardless of what you set in the designer. Also, maybe building the project before accessing this field would help.

Enc Rypt17y ago

thanks for the fast reply, but i seem to be getting a compiling error:

 error CS0118: 'TestProject.Form1.Options' is a 'field' but is used like a 'type'

 private void form1_Resize(object sender, EventArgs e)
 {
     Form f = Application.OpenForms["Options"];
     bool CheckBox1State = ((Options)f).checkBox1.Checked;
     if (this.WindowState == FormWindowState.Minimized == true && CheckBox1State == true)
     {
         notifyIcon1.Visible = true;
         this.WindowState = FormWindowState.Minimized;
         this.ShowInTaskbar = false;
     }
 }

Kirtan Patel17y ago
Friend,
Here is code for what you are trying to do Here Requirement is Your Options Form Should Be Open to Access the
CheckBox in It :)

dont forget to mark "Do you like this answer" if my answer helped you :)

Step 1

Make CheckBox1's Property "Modifire = "Public" in Options Form like below image

Then Write Code Like Below Where ever you want to access CheckBox

           //Get CheckBox1State in Options
            Form f = Application.OpenForms["Options"];
            bool CheckBox1State = ((Options)f).checkBox1.Checked;

            if (this.WindowState == FormWindowState.Minimized == true && CheckBox1State == true)
            {
                notifyIcon1.Visible = true;
                this.WindowState = FormWindowState.Minimized;
                this.ShowInTaskbar = false;
            }