ErrorProvider.GetError メソッド

.NET Framework クラス ライブラリ リファレンス

ErrorProvider.GetError メソッド

指定したコントロールの現在のエラーを説明する文字列を返します。

名前空間: System.Windows.Forms
アセンブリ: System.Windows.Forms (system.windows.forms.dll 内)
構文

Visual Basic (宣言)

<LocalizableAttribute(True)> _
Public Function GetError ( _
    control As Control _
) As String

Visual Basic (使用法)

Dim instance As ErrorProvider
Dim control As Control
Dim returnValue As String

returnValue = instance.GetError(control)

C#

[LocalizableAttribute(true)] 
public string GetError (
    Control control
)

C++

[LocalizableAttribute(true)] 
public:
String^ GetError (
    Control^ control
)

J#

/** @attribute LocalizableAttribute(true) */ 
public String GetError (
    Control control
)

JScript

LocalizableAttribute(true) 
public function GetError (
    control : Control
) : String

パラメータ

control

エラーを説明する文字列を取得する対象となる項目。

戻り値
指定したコントロールの現在のエラーを説明する文字列。

例外

例外の種類	条件
ArgumentNullException	control が null 参照 (Visual Basic では Nothing) です。

使用例

次のコード例では、GetError メソッドを使用して、ファイル ダイアログ ボックスを開く前にエラーがあるかどうかを調べます。この例を実行するには、TextBox1 という名前の TextBox、OpenFileDialog1 という名前の OpenFileDialog、Button1 という名前のボタン、および ErrorProvider1 という名前の ErrorProvider が配置されているフォームに次のコードを貼り付けます。必ずすべてのイベントをイベント ハンドラに関連付けるようにしてください。

Visual Basic

Private Sub TextBox1_Validating(ByVal
 sender As Object, _
ByVal e As System.ComponentModel.CancelEventArgs)
 _
Handles TextBox1.Validating

    ' If nothing is entered,
    ' an ArgumentException is caught; if an invalid directory is entered,
 
    ' a DirectoryNotFoundException is caught. An appropriate error message
 
    ' is displayed in either case.
    Try
        Dim directory As New
 System.IO.DirectoryInfo(TextBox1.Text)
        directory.GetFiles()
        ErrorProvider1.SetError(TextBox1, "")

    Catch ex1 As System.ArgumentException
        ErrorProvider1.SetError(TextBox1, "Please enter a directory")

    Catch ex2 As System.IO.DirectoryNotFoundException
        ErrorProvider1.SetError(TextBox1, _
        "The directory does not exist." & _
        "Try again with a different directory.")
    End Try

End Sub

' This method handles the LostFocus event for TextBox1 by setting the
 
' dialog's InitialDirectory property to the text in TextBox1.
Private Sub TextBox1_LostFocus(ByVal
 sender As Object, _
    ByVal e As System.EventArgs) Handles
 TextBox1.LostFocus
    OpenFileDialog1.InitialDirectory = TextBox1.Text
End Sub


' This method demonstrates using the ErrorProvider.GetError method 
' to check for an error before opening the dialog box.
Private Sub Button1_Click(ByVal
 sender As System.Object, _
ByVal e As System.EventArgs) Handles
 Button1.Click

    'If there is no error, then open the dialog box.
    If ErrorProvider1.GetError(TextBox1) = ""
 Then
        Dim dialogResult As DialogResult =
 OpenFileDialog1.ShowDialog()
    End If

End Sub

C#

private void TextBox1_Validating(object sender,
 
    System.ComponentModel.CancelEventArgs e)
{
    // If nothing is entered,
    // an ArgumentException is caught; if an invalid directory is entered,
 
    // a DirectoryNotFoundException is caught. An appropriate error
 message 
    // is displayed in either case.
    try
    {
        System.IO.DirectoryInfo directory = 
            new System.IO.DirectoryInfo(TextBox1.Text);
        directory.GetFiles();
        ErrorProvider1.SetError(TextBox1, "");

    }
    catch(System.ArgumentException ex1)
    {
        ErrorProvider1.SetError(TextBox1, "Please enter a directory");

    }
    catch(System.IO.DirectoryNotFoundException ex2)
    {
        ErrorProvider1.SetError(TextBox1, "The directory does not exist."
 +
            "Try again with a different directory.");
    }

}

// This method handles the LostFocus event for TextBox1 by setting the
 
// dialog's InitialDirectory property to the text in TextBox1.
private void TextBox1_LostFocus(object sender,
 System.EventArgs e)
{
    OpenFileDialog1.InitialDirectory = TextBox1.Text;
}

// This method demonstrates using the ErrorProvider.GetError method
 
// to check for an error before opening the dialog box.
private void Button1_Click(System.Object sender,
 System.EventArgs e)
{
    //If there is no error, then open the dialog box.
    if (ErrorProvider1.GetError(TextBox1)=="")
    {
        DialogResult dialogResult = OpenFileDialog1.ShowDialog();
    }
}

C++

private:
   void TextBox1_Validating( Object^ sender,
      System::ComponentModel::CancelEventArgs^ e )
   {
      // If nothing is entered,
      // an ArgumentException is caught; if an invalid directory is entered,
 
      // a DirectoryNotFoundException is caught. An appropriate error
 message 
      // is displayed in either case.
      try
      {
         System::IO::DirectoryInfo^ directory = gcnew System::IO::DirectoryInfo(
 TextBox1->Text );
         directory->GetFiles();
         ErrorProvider1->SetError( TextBox1, "" );
      }
      catch ( System::ArgumentException^ ) 
      {
         ErrorProvider1->SetError( TextBox1, "Please enter a directory"
 );
      }
      catch ( System::IO::DirectoryNotFoundException^ ) 
      {
         ErrorProvider1->SetError( TextBox1, "The directory does not exist."
         "Try again with a different directory." );
      }
   }

   // This method handles the LostFocus event for TextBox1 by setting the
 
   // dialog's InitialDirectory property to the text in TextBox1.
   void TextBox1_LostFocus( Object^ sender, System::EventArgs^
 e )
   {
      OpenFileDialog1->InitialDirectory = TextBox1->Text;
   }

   // This method demonstrates using the ErrorProvider.GetError method
 
   // to check for an error before opening the dialog box.
   void Button1_Click( System::Object^ sender, System::EventArgs^
 e )
   {
      //If there is no error, then open the dialog box.
      if ( ErrorProvider1->GetError( TextBox1 )->Equals(
 "" ) )
      {
         ::DialogResult dialogResult = OpenFileDialog1->ShowDialog();
      }
   }

J#

private void textBox1_Validating(Object sender,
 
    System.ComponentModel.CancelEventArgs e)
{
    // If nothing is entered,
    // an ArgumentException is caught; if an invalid directory is entered,
 
    // a DirectoryNotFoundException is caught. An appropriate error
 message 
    // is displayed in either case.
    try {
        System.IO.DirectoryInfo directory = new System.IO.DirectoryInfo(
            textBox1.get_Text());
        directory.GetFiles();
        errorProvider1.SetError(textBox1, "");
    }
    catch (System.ArgumentException ex1) {
        errorProvider1.SetError(textBox1, "Please enter a directory");
    }
    catch (System.IO.DirectoryNotFoundException ex2) {
        errorProvider1.SetError(textBox1, "The directory does not exist."
 
            + "Try again with a different directory.");
    }
} //textBox1_Validating

// This method handles the LostFocus event for textBox1 by setting the
 
// dialog's InitialDirectory property to the text in textBox1.
private void textBox1_LostFocus(Object sender,
 System.EventArgs e)
{
    openFileDialog1.set_InitialDirectory(textBox1.get_Text());
} //textBox1_LostFocus

// This method demonstrates using the ErrorProvider.GetError method
 
// to check for an error before opening the dialog box.
private void button1_Click(Object sender, System.EventArgs
 e)
{
    //If there is no error, then open the dialog box.
    if (errorProvider1.GetError(textBox1).Equals(""))
 {
        DialogResult dialogResult = openFileDialog1.ShowDialog();
    }
} //button1_Click

プラットフォーム

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0

参照

関連項目
ErrorProvider クラス
ErrorProvider メンバ
System.Windows.Forms 名前空間
SetError