In asp.net, values are transferred between the child window and the parent window by Delegate and event.

This article introduces asp.net's implementation of passing values between the child window and the parent window through delegation and events. There are two methods, one is to pass the parent window to the Child window, set the attribute or resource of the parent window to public, and use the delegate event for handling. For more information, see.

The following method uses a delegate event to implement the above functions:

Take logon as an example. The subform AccountWindow:

① Define delegation:

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Public delegate void LoginSuccessedDelegate (object sender, LoginSuccessedEventArgs e ); Public event LoginSuccessedDelegate LoginSuccessedEvent;

② Event pass value:

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Private void LoginButton_Click (object sender, RoutedEventArgs e) { This. Close (); LoginSuccessedEventArgs loginAccount = new LoginSuccessedEventArgs (); LoginAccount. Account = "123" + DateTime. Now. Second. ToString (); LoginSuccessedEvent (sender, loginAccount ); } // Define the data type of the passed Value Public class LoginSuccessedEventArgs: EventArgs { Public string Account {get; set ;} }

Parent form:

① Trigger a logon event

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Private void Login_Click (object sender, RoutedEventArgs e) { AccountWindow accountWindow = new AccountWindow (this ); // Register an event AccountWindow. LoginSuccessedEvent + = new AccountWindow. LoginSuccessedDelegate (accountWindow_LoginSuccessedEvent ); AccountWindow. ShowDialog (); }

② Handle the return value of a successful logon event (in this case, we can obtain the return value for logon and operate the attributes and resources of the parent form based on the return value, saving the need to pass the parent form to the child form)

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Void accountWindow_LoginSuccessedEvent (object sender, AccountWindow. LoginSuccessedEventArgs e) { UserInfo. Content = "Current Account:" + e. Account; }