Parent Child Communication

Parent Child Communication

• jaswinder_rana

  Attach a method of the parent form to the validate event of the child form. . . .

  This is c# because vb is not worth using. . .

  assumes a form,  called ChildForm, has two buttons, one with a dialog result of DialogResult.Ok the other with DialogResult.Cancel. Form1 wants to check that the data is ok when the user clicks Ok on ChildForm otherwise, let it close.

      public partial class Form1 : Form
      {
          private void button1_Click(object sender, EventArgs e)
          {
              using (ChildForm frm = new ChildForm())
              {
                  frm.FormClosing += new FormClosingEventHandler(CheckChild);
                  if (frm.ShowDialog() == DialogResult.OK)
                      InitializeApp();
                  frm.Validating -= new CancelEventHandler(CheckChild);
              }
          }

          private void CheckChild(object sender, CancelEventArgs e)
          {
              ChildForm frm = sender as ChildForm;
              if (frm != null)
              {
                  if (frm.DialogResult == DialogResult.OK)
                      e.Cancel = !EvaluateChild(frm);
              }
          }

          private void InitializeApp()
          {
              //setup app here
          }

          private void EvaluateChild(ChildForm frm)
          {
              // check ChildForm data here. Return True if ChildForm has valid data
          }
      }
  

   

  
  
  

• Padma G

  hi,

  what do you mean by parent and child

  do you mean data relations,  xml nodes ,  treeview nodes, or what you have to make your question  clear more than that

  bye

  
  
  

• Lost Web Owner

  hi,

  ok my friend really i never try this login form b4 but i tried for now and i was able to code on it just right click and chose view code and you can code it , it accepted from me at least , by the way the login form has a link to talking about how to make it

  here its the main form load method

  Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

  Dim myloginform As New LoginForm1

  myloginform.ShowDialog()

  MessageBox.Show(myloginform.username & vbNewLine & myloginform.password)

  myloginform = Nothing

  End Sub

  and here its the login form class by the way it has a link by default from microsoft to teach you something about it

  Public Class LoginForm1

  ' TODO: Insert code to perform custom authentication using the provided username and password

  ' (See http://go.microsoft.com/fwlink/ LinkId=35339).

  ' The custom principal can then be attached to the current thread's principal as follows:

  ' My.User.CurrentPrincipal = CustomPrincipal

  ' where CustomPrincipal is the IPrincipal implementation used to perform authentication.

  ' Subsequently, My.User will return identity information encapsulated in the CustomPrincipal object

  ' such as the username, display name, etc.

  Private _username As String

  Private _password As String

  ReadOnly Property username()

  Get

  Return _username

  End Get

  End Property

  ReadOnly Property password()

  Get

  Return _password

  End Get

  End Property

  Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click

  If Me.UsernameTextBox.Text = "myname" AndAlso Me.PasswordTextBox.Text = "123456" Then

  _username = Me.UsernameTextBox.Text

  _password = Me.PasswordTextBox.Text

  Me.Close()

  Else

  MessageBox.Show("enterusername")

  End If

  End Sub

  Private Sub Cancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Cancel.Click

  Me.Close()

  End Sub

   

  End Class

   

  
  
  

• Wolfwang

  oooppppss!

  this:

                frm.FormClosing += new FormClosingEventHandler(CheckChild);
                  if (frm.ShowDialog() == DialogResult.OK)
                      InitializeApp();
                  frm.Validating -= new CancelEventHandler(CheckChild);

  should have read:

                frm.FormClosing += new FormClosingEventHandler(CheckChild);
                  if (frm.ShowDialog() == DialogResult.OK)
                      InitializeApp();
                  frm.FormClosing -= new FormClosingEventHandler(CheckChild);

  
  
  

• bapper1

  Thankyou for ur guidence

   

  
  
  

• Hans-Gustav

  Thankyou for ur guidence

  I will look forward to ask more from u about this language in future, also it is much better to have ur id so that i can directly mail u

  Thankyou

  
  
  

• Ali Baradaran

  Well i am in a situation that there is a main form which has a sub login form as in studio 2005 edition we can add new login form but we can't code on it hope u see that, what i want to do is i want to check wether the username and password enter in the login window is correct by my main form. As my main form is Parent form and login form is its child.

  If u are still not clear then open 2005 studio edition make a form and add login form to it and see by ureself u cannt code on login form directly u have to code for it on the main form

  Thankyou.

  
  
  
• Parent Child Communication