Forms seeing other forms

Richard Brennan

I have 2 forms in my app at the moment. The main form calls another form from a menu option. I have got that working. On the second form, when OK is clicked I want to close the from (easy) and make the first form become active again. But the code is on the btnClick on the second form and I can't seen to access the first from enable or show properties.

So I suppose the question is - how do u make a control on one form access the properties on a different form.

i have tried

frmMain.show()
frmMain.Enable();

but the .show() or .enable() are not appearing on intelli type (or what ever its called).

13 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes15y ago
Accepted answer
If you do need to restore it, then you can do so by setting its WindowState property to FormWindowState.Normal.

I assume you have a reference to the main form somewhere? If not, you can get one using Application.OpenForms:

frmLogOn main = (frmLogOn)Application.OpenForms["frmLogon"];
main.WindowState = FormWindowState.Normal;
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Richard Brennan15y ago
thanx vulpers - that took some getting out of u all. May be due to my unclear original question. Big sigh of releif.

Thanx for all your input every one. Lets close this one - finally lol.
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Sam Hobbs15y ago
Richard, it is not clear to me whether your question about minimizing is relevant to Frogleg's code. I assume it is not and therefore before I can help I need to understand how the form gets minimized. Note that "get a form back that i have minimised" is usually called restoring the window or form.

Are you sure you need to minimize the form? Another possibility would be to hide it, then show it again when the other window is closed.. Another possibility would be to show the other form as a dialog, and then the system will automatically take care of disabling the main form while the other form is shown. Another possibility is to show/hide both forms as appropriate (show one and hide the other).
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Richard Brennan15y ago
vulpes - how do i get a form back that i have minimised. I need to get it back from a button on a different form.

The situation

Main form: LogOn
Otherform: Change PAssword

On the main form - there is a change password option. When selected 'main form' minimises and Otherform appeares. Thats fine.
The problem is when i click ok on otherform - i can hide otherform - but i cangt get 'main form' to come back. The code above is the code i currently have on otherform. I hope that clarifies the situation for all u keen helpers.
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Vulpes15y ago
Using the Hide() method is in fact equivalent to setting the Visible property to 'false' so it doesn't matter which you use.

You should only use Close() when you've finished with the form altogether. If you close the startup form, then this will cause all other forms to close and the application itself to terminate.
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Richard Brennan15y ago
Frogleg – ur example seem to be hitting the nail – but i can't extrapolate your example to my needs. Is using hide() better than visible = false? Should close() only be used as the app is exited?
My problem in detail, I have a main form with the following code:
frmSplash frmSplash = new frmSplash();
frmAbout frmAbout = new frmAbout();
frmChangePassword frmChangePassword = new frmChangePassword();
frmStudent frmStudent = new frmStudent();
frmStaff frmStaff = new frmStaff();
frmAdmin frmAdmin = new frmAdmin();

and all these forms can be opened from the mainform (frmLogOn in this case).
When change password is selected, this code is used.
private void changePassword()
{
this.WindowState = FormWindowState.Minimized; //minimize logon form
frmChangePassword.ShowDialog(); //show change password form
}

EVERY THING OK SO FAR ;)
On the change password form has code
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace Web_Spinner
{
public partial class frmChangePassword : Form
{
public frmChangePassword()
{
InitializeComponent();
}

private void frmChangePassword_Load(object sender, EventArgs e)
{
this.txtChangePasswordUsername.Focus();
}

//Buttons
#region buttons
private void btnChangePasswordOk_Click(object sender, EventArgs e)
{
bool valid = true;
//validate user name and password
if (valid)
{
//update password
I want to hide the current form: .hide() i guess is best ;)
I then want get the logon Form showing. Every time I use
frmLogOn. nothing that i know how to use comes up.

do i have to add
frmLogOn frmLogOn = new frmLogOn();
frmLogOn.Show(); - and if so will this make multiple instances of this form as it was opened when the program was first loaded?

Probably very simple but Im a self taught newby and simple things are sometimes confusing lol.
}
else
{
this.txtChangePasswordUsername.Text = "";
this.txtChangePasswordPassword.Text = "";
this.txtChangePasswordNewPassword.Text = "";
this.txtChangePasswordConfirmPassword.Text = "";
this.txtChangePasswordUsername.Focus();
}

}

}
}
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Karthikeyan Anbarasan15y ago
Richard, please explain your question briefly... so that we can work it out for u
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Sam Hobbs15y ago
Richard, can you please calrify what you need? I think everyone is trying to guess at what you need and this thread will continue to grow and we are just confusing you further.
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piyush sardhara15y ago
you can use 2 panel

1st from in 1st panel
and
2nd from in 2 panel

then to use 2 from

1st panel visible =flase;

and otherwise

panel 1 is visible =true;

you can try it;
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Vulpes15y ago
A simple way to obtain a reference to another form in the application, without disrupting existing code, is to use the Application.OpenForms property and then use its Controls collection to get a reference to a particular control.

Suppose you have a form whose class is called SomeForm and you want to set textBox1's Text property on that form. The code to do this from a different form would be:

SomeForm sf = (SomeForm)Application.OpenForms["SomeForm"];
TextBox tb = (TextBox)sf.Controls["textBox1"];
tb.Text = "Hello from a different form";
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Frogleg15y ago
Try this
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Sahil Jani15y ago
Hi Richard,

I think you have given the link of the 2nd form in menu option. Likewise, you just give the link of the 1st form to the button.

protected void button1_Click(object sender, EventArgs e)
{
        String url = "~/form1.aspx?" + "" + "Action=approve";
        Response.Redirect(url);
        String queryString = null;
        if (Request.QueryString["Action"] != null)
        {
                queryString = Request.QueryString["Action"].ToString();
        }
        else if (queryString == "approve")
        {
                //
        }
}

This code might help to you.

If it will help it to you then marked this answer as "ACCEPTED ANSWER"
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Sam Hobbs15y ago
It is not clear to me what you are asking.

First I will say that it is highly unlikely you need to access the first form from the second one, especially if you are doing what I think you are doing.

How are you showing the second form from the first? Are you using ShowDialog or Show? ShowDialog will make the form modal and Show will make it modeless. Modal means that the first form cannot be used again until the second form is closed. Modeless means that both can be used at the same time. My guess is that you want to make the second form modal so use ShowDialog.
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