Control.Validating Kejadian

Definisi

Ruang nama:

System.Windows.Forms

Rakitan:

System.Windows.Forms.dll

Terjadi ketika kontrol memvalidasi.

public:
 event System::ComponentModel::CancelEventHandler ^ Validating;

public event System.ComponentModel.CancelEventHandler? Validating;

member this.Validating : System.ComponentModel.CancelEventHandler 

Public Custom Event Validating As CancelEventHandler 

Jenis Acara

CancelEventHandler

Contoh

Contoh kode berikut menggunakan kelas TextBox turunan dan memvalidasi alamat email yang dimasukkan pengguna. Jika alamat email tidak dalam format standar (berisi "@" dan "."), validasi gagal, ErrorProvider ikon ditampilkan, dan acara dibatalkan. Contoh ini mengharuskan kontrol TextBox dan ErrorProvider telah dibuat pada formulir.

private:
   void textBox1_Validating( Object^ sender, System::ComponentModel::CancelEventArgs^ e )
   {
      String^ errorMsg;
      if ( !ValidEmailAddress( textBox1->Text, &errorMsg ) )
      {
         // Cancel the event and select the text to be corrected by the user.
         e->Cancel = true;
         textBox1->Select( 0, textBox1->Text->Length );
         
         // Set the ErrorProvider error with the text to display.
         this->errorProvider1->SetError( textBox1, errorMsg );
      }
   }

   void textBox1_Validated( Object^ sender, System::EventArgs^ e )
   {
      // If all conditions have been met, clear the ErrorProvider of errors.
      errorProvider1->SetError( textBox1, "" );
   }

public:
   bool ValidEmailAddress( String^ emailAddress, [Out]interior_ptr<String^> errorMessage )
   {
      // Confirm that the email address String* is not empty.
      if ( emailAddress->Length == 0 )
      {
         *errorMessage = "email address is required.";
         return false;
      }

      // Confirm that there is an "@" and a "." in the email address, and in the correct order.
      if ( emailAddress->IndexOf( "@" ) > -1 )
      {
         if ( emailAddress->IndexOf( ".", emailAddress->IndexOf( "@" ) ) > emailAddress->IndexOf( "@" ) )
         {
            *errorMessage = "";
            return true;
         }
      }

      *errorMessage = "email address must be valid email address format.\n" +
         "For example 'someone@example.com' ";
      return false;
   }

private void textBox1_Validating(object sender, 
                System.ComponentModel.CancelEventArgs e)
{
   string errorMsg;
   if(!ValidEmailAddress(textBox1.Text, out errorMsg))
   {
      // Cancel the event and select the text to be corrected by the user.
      e.Cancel = true;
      textBox1.Select(0, textBox1.Text.Length);

      // Set the ErrorProvider error with the text to display. 
      this.errorProvider1.SetError(textBox1, errorMsg);
   }
}

private void textBox1_Validated(object sender, System.EventArgs e)
{
   // If all conditions have been met, clear the ErrorProvider of errors.
   errorProvider1.SetError(textBox1, "");
}
public bool ValidEmailAddress(string emailAddress, out string errorMessage)
{
   // Confirm that the email address string is not empty.
   if(emailAddress.Length == 0)
   {
      errorMessage = "email address is required.";
         return false;
   }

   // Confirm that there is an "@" and a "." in the email address, and in the correct order.
   if(emailAddress.IndexOf("@") > -1)
   {
      if(emailAddress.IndexOf(".", emailAddress.IndexOf("@") ) > emailAddress.IndexOf("@") )
      {
         errorMessage = "";
         return true;
      }
   }
   
   errorMessage = "email address must be valid email address format.\n" +
      "For example 'someone@example.com' ";
      return false;
}

   Private Function ValidEmailAddress(ByVal emailAddress As String, ByRef errorMessage As String) As Boolean
      ' Confirm there is text in the control.
      If textBox1.Text.Length = 0 Then
         errorMessage = "Email address is required."
         Return False

      End If

      ' Confirm that there is an "@" and a "." in the email address, and in the correct order.
      If emailAddress.IndexOf("@") > -1 Then
         If (emailAddress.IndexOf(".", emailAddress.IndexOf("@")) > emailAddress.IndexOf("@")) Then
            errorMessage = ""
            Return True
         End If
      End If

      errorMessage = "Email address must be valid email address format." + ControlChars.Cr + _
        "For example 'someone@example.com' "
      Return False
End Function

   Private Sub textBox1_Validating(ByVal sender As Object, _
   ByVal e As System.ComponentModel.CancelEventArgs) Handles textBox1.Validating

      Dim errorMsg As String
      If Not ValidEmailAddress(textBox1.Text, errorMsg) Then
         ' Cancel the event and select the text to be corrected by the user.
         e.Cancel = True
         textBox1.Select(0, textBox1.Text.Length)

         ' Set the ErrorProvider error with the text to display. 
         Me.errorProvider1.SetError(textBox1, errorMsg)
      End If
   End Sub


   Private Sub textBox1_Validated(ByVal sender As Object, _
   ByVal e As System.EventArgs) Handles textBox1.Validated
      ' If all conditions have been met, clear the error provider of errors.
      errorProvider1.SetError(textBox1, "")
   End Sub

Keterangan

Saat Anda mengubah fokus dengan menggunakan keyboard (TAB, SHIFT+TAB, dan sebagainya), dengan memanggil Select metode atau SelectNextControl , atau dengan mengatur ContainerControl.ActiveControl properti ke formulir saat ini, peristiwa fokus terjadi dalam urutan berikut:

1. Enter

2. GotFocus

3. Leave

4. Validating

5. Validated

6. LostFocus

Saat Anda mengubah fokus dengan menggunakan mouse atau dengan memanggil Focus metode , peristiwa fokus terjadi dalam urutan berikut:

1. Enter

2. GotFocus

3. LostFocus

4. Leave

5. Validating

6. Validated

CausesValidation Jika properti diatur ke false, Validating peristiwa dan Validated ditekan.

Cancel Jika properti diatur CancelEventArgs ke true dalam Validating delegasi peristiwa, semua peristiwa yang biasanya akan terjadi setelah Validating peristiwa ditekan.

Perhatian

Jangan mencoba untuk mengatur fokus dari dalam Enterpenanganan aktivitas , , LeaveGotFocus, LostFocus, Validatingatau Validated . Melakukannya dapat menyebabkan aplikasi Anda atau sistem operasi berhenti merespons. Untuk informasi selengkapnya, lihat WM_KILLFOCUS topik di bagian "Referensi Input Keyboard", dan bagian "Kebuntuan Pesan" dari artikel Tentang Pesan dan Antrean Pesan .

Untuk informasi selengkapnya tentang menangani peristiwa, lihat Menangani dan Menaikkan Peristiwa.

Lihat juga

• OnValidating(CancelEventArgs)
• CausesValidation
• Validated