C# : Sending data from one form to other using delegates : Part 27

Flow

• Select the form whom you wish to send the data, who all are the subscribers to the notification.
• This will make you to decide the type of parameter that you wish to send and to be used in delegates.
• Then it is necessary to decide which form will be sending notification, or it can be also said that who is the owner.

Steps

• Declare the delegate
• Create the variable of delegate
• When you initialize the form point/assign the method to the delegate
• Call the delegate when required and pass the parameter.

Main Form / Owner Form code

 namespace Delegates  
 {  
   public partial class MainForm : Form  
   {  
     public delegate void SetTextValueCallback(string str);  
     public SetTextValueCallback SetTextValue;  
     public MainForm()  
     {  
       InitializeComponent();  
     }  
     private void MainForm_Load(object sender, EventArgs e)  
     {  
     }  
     private void btnShowForm_Click(object sender, EventArgs e)  
     {  
       ChildForm frm = new ChildForm();  
       this.SetTextValue += new SetTextValueCallback(frm.SetText);  
       frm.Show();  
     }  
     private void btnAppend_Click(object sender, EventArgs e)  
     {  
       SetTextValue(txtEnterText.Text);  
     }  
   }  
 }  

Child Form / Subscriber Form

 namespace Delegates  
 {  
   public partial class ChildForm : Form  
   {  
     public ChildForm()  
     {  
       InitializeComponent();  
     }  
     private void ChildForm_Load(object sender, EventArgs e)  
     {  
     }  
     public void SetText(string str)  
     {  
       lblAppendedText.Text = str;  
     }  
   }  
 }