Control.Validating Kejadian
Definisi
Penting
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Terjadi ketika kontrol memvalidasi.
public:
event System::ComponentModel::CancelEventHandler ^ Validating;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
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:
Saat Anda mengubah fokus dengan menggunakan mouse atau dengan memanggil Focus metode , peristiwa fokus terjadi dalam urutan berikut:
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.
