Retrievng values from 1 form to other form in the same solution

Create one set property in second form like

public String FirstFormText
        {
           set { textBox1.Text = value; }

        }

Assign TextBox value to second form property this will call set method in property and assign your text to second form text box

frm.FirstFormText = textBox1.Text; 

Thanks for the thoughts BillWoodruff, I have modified the code now so that the form2 does not needs to be opened from form1 and hope this resolves the issue

1. Define the following under the form2 class

public static Form IsFormAlreadyOpen(Type FormType)
        {
            foreach (Form OpenForm in Application.OpenForms)
            {
                if (OpenForm.GetType() == FormType)
                    return OpenForm;
            }

            return null;
        }

2.Add a button in form 2 and the code behind is

private void button1_Click(object sender, EventArgs e)
       {
           if ((Form1)IsFormAlreadyOpen(typeof(Form1)) != null)
           {
               var x = (Form1)IsFormAlreadyOpen(typeof(Form1));
               MessageBox.Show(x.textBox1.Text);

           } else {

               MessageBox.Show("The forms is not opened");
           }
       }

3. click the button on form 2 will retrieve the value in form1 Textbox1.

This does not need the form2 to be called from form1 and returns the Textbox1 value at that time the button is clicked.

Hope this helps

suppose your app has 2 forms

form1 & form2

and you need value of form 1 on form 2

there are 2 methods

1st one is you make a class that contains static variable .
so assign value to then and access where you want in your application.

2nd one is
make the constructor of form 2

after Initiliase Component of form2

int val;
Form2 =new Form2(int myVal)
{
val=myval;
}

You've got some technical answers already. But this is a design problem. If two forms need to look at the same data, that data should be in a separate data store, not in either form; the forms should just be (interactive) views on the data. Look into data binding and separation of data and UI; if using WPF, read up on MVVM.

The same data model should be bound to both forms, so that when the user types something on one form, it updates the data model, and notifies the binding mechanism so that the other control(s) which are bound to it can update themselves. Typically that notification is done through INotifyPropertyChanged.

There are a few cases where it is reasonable to directly access another form: in particular, if the second form is a subsidiary of the first (e.g. a dialogue created by pressing a button on the first), and it is modal (so you don't have synchronisation problems). Two forms which can be active at the same time pointing at the same data should be bound to an external data object, because that data clearly does not 'belong' to either form.