Frequently when writing winforms applications, one needs to call a method/function in another form. This is very handy for instance, if you want to refresh the other form after changing values in a database.
After trying to solve this using delegates, I came across this eloquent solution.
Create two Winforms, F1 and F2 with a button in each.
In Form 1
using System; using System.Windows.Forms; namespace WindowsFormsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } public void MyMessage() { MessageBox.Show("Hello from Form 1"); } private void button1_Click(object sender, EventArgs e) { Form2 form2 = new Form2(this); form2.ShowDialog(this); } } }
In Form 2
using System; using System.Windows.Forms; namespace WindowsFormsApplication1 { public partial class Form2 : Form { Form1 form1; public Form2(Form1 form1) { InitializeComponent(); this.form1 = form1; } private void button1_Click(object sender, EventArgs e) { this.form1.MyMessage(); } } }
The instance of form 1 is passed to the second form using the this keyword. Ultimately what is passed is just a reference (pointer) to the form object.
Ira Lukhezo's blog 