Nasıl yapılır: Klavye Girdisini Form Düzeyinde İşleme

Makale
10/19/2023

Windows Forms, klavye iletilerinin denetime ulaşmadan önce form düzeyinde işlenmesini sağlar. Bu konu başlığında bu görevin nasıl yerine getir adımları gösterilmektedir.

Bir klavye iletisini form düzeyinde işlemek için

Başlangıç formunun KeyPress veya KeyDown olayını işleyip formun true özelliğini olarak ayarlayarak klavye iletilerinin formdaki denetimlere ulaşmadan önce form tarafından alınmasını sağlayınKeyPreview. Aşağıdaki kod örneği, tüm sayı anahtarlarını algılayarak ve '1', '4' ve '7' kullanarak olayı işler KeyPress .

    // Detect all numeric characters at the form level and consume 1,
    // 4, and 7. Note that Form.KeyPreview must be set to true for this
    // event handler to be called.
private:
    void Form1_KeyPress(Object^ sender, KeyPressEventArgs^ e)
    {
        if ((e->KeyChar >= '0') && (e->KeyChar <= '9'))
        {
            MessageBox::Show("Form.KeyPress: '" +
                e->KeyChar.ToString() + "' pressed.");

            switch (e->KeyChar)
            {
            case '1':
            case '4':
            case '7':
                MessageBox::Show("Form.KeyPress: '" +
                    e->KeyChar.ToString() + "' consumed.");
                e->Handled = true;
                break;
            }
        }
    }

// Detect all numeric characters at the form level and consume 1,
// 4, and 7. Note that Form.KeyPreview must be set to true for this
// event handler to be called.
void Form1_KeyPress(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar >= 48 && e.KeyChar <= 57)
    {
        MessageBox.Show("Form.KeyPress: '" +
            e.KeyChar.ToString() + "' pressed.");

        switch (e.KeyChar)
        {
            case (char)49:
            case (char)52:
            case (char)55:
                MessageBox.Show("Form.KeyPress: '" +
                    e.KeyChar.ToString() + "' consumed.");
                e.Handled = true;
                break;
        }
    }
}

' Detect all numeric characters at the form level and consume 1, 
' 4, and 7. Note that Form.KeyPreview must be set to true for this
' event handler to be called.
Sub Form1_KeyPress(ByVal sender As Object, _
    ByVal e As KeyPressEventArgs) Handles Me.KeyPress

    If e.KeyChar >= ChrW(48) And e.KeyChar <= ChrW(57) Then
        MessageBox.Show(("Form.KeyPress: '" + _
            e.KeyChar.ToString() + "' pressed."))

        Select Case e.KeyChar
            Case ChrW(49), ChrW(52), ChrW(55)
                MessageBox.Show(("Form.KeyPress: '" + _
                    e.KeyChar.ToString() + "' consumed."))
                e.Handled = True
        End Select
    End If
End Sub

Örnek

Aşağıdaki kod örneği, yukarıdaki örnek için uygulamanın tamamıdır. Uygulama, odağı uygulamasından TextBoxtaşımanıza olanak sağlayan diğer birçok denetimle birlikte bir TextBox içerir. KeyPress Ana Form olay '1', '4' ve '7' tüketir ve KeyPress olay TextBox kalan anahtarları görüntülerken '2', '5' ve '8' tüketir. Bir sayı tuşuna MessageBox TextBox bastığınızda, odak diğer denetimlerden birindeyken bir sayı tuşuna bastığınızda çıkışı çıkışla MessageBox karşılaştırın.

#using <System.Drawing.dll>
#using <System.Windows.Forms.dll>
#using <System.dll>

using namespace System;
using namespace System::Drawing;
using namespace System::Windows::Forms;
using namespace System::Security::Permissions;

namespace KeyboardInputForm
{
    public ref class Form1 sealed: public Form, public IMessageFilter
    {
        // The following Windows message value is defined in Winuser.h.
    private:
        static const int WM_KEYDOWN = 0x100;
    private:
        TextBox^ inputTextBox;
    public:
        Form1()
        {
            inputTextBox = gcnew TextBox();
            this->AutoSize = true;
            Application::AddMessageFilter(this);
            FlowLayoutPanel^ panel = gcnew FlowLayoutPanel();
            panel->AutoSize = true;
            panel->FlowDirection = FlowDirection::TopDown;
            panel->Controls->Add(gcnew Button());
            panel->Controls->Add(gcnew RadioButton());
            panel->Controls->Add(inputTextBox);
            this->Controls->Add(panel);
            this->KeyPreview = true;
            this->KeyPress +=
                gcnew KeyPressEventHandler(this, &Form1::Form1_KeyPress);
            inputTextBox->KeyPress +=
                gcnew KeyPressEventHandler(this,
                &Form1::inputTextBox_KeyPress);
        }

        // Detect all numeric characters at the
        // application level and consume 0.
        virtual bool PreFilterMessage(Message% m)
        {
            // Detect key down messages.
            if (m.Msg == WM_KEYDOWN)
            {
                Keys keyCode =  (Keys)((int)m.WParam) & Keys::KeyCode;
                // Determine whether the keystroke is a number from the top of
                // the keyboard, or a number from the keypad.
                if (((keyCode >= Keys::D0) && (keyCode <= Keys::D9))
                    ||((keyCode >= Keys::NumPad0)
                    && (keyCode <= Keys::NumPad9)))
                {
                    MessageBox::Show(
                        "IMessageFilter.PreFilterMessage: '" +
                        keyCode.ToString() + "' pressed.");

                    if ((keyCode == Keys::D0) || (keyCode == Keys::NumPad0))
                    {
                        MessageBox::Show(
                            "IMessageFilter.PreFilterMessage: '" +
                            keyCode.ToString() + "' consumed.");
                        return true;
                    }
                }
            }

            // Forward all other messages.
            return false;
        }

        // Detect all numeric characters at the form level and consume 1,
        // 4, and 7. Note that Form.KeyPreview must be set to true for this
        // event handler to be called.
    private:
        void Form1_KeyPress(Object^ sender, KeyPressEventArgs^ e)
        {
            if ((e->KeyChar >= '0') && (e->KeyChar <= '9'))
            {
                MessageBox::Show("Form.KeyPress: '" +
                    e->KeyChar.ToString() + "' pressed.");

                switch (e->KeyChar)
                {
                case '1':
                case '4':
                case '7':
                    MessageBox::Show("Form.KeyPress: '" +
                        e->KeyChar.ToString() + "' consumed.");
                    e->Handled = true;
                    break;
                }
            }
        }

        // Detect all numeric characters at the TextBox level and consume
        // 2, 5, and 8.
    private:
        void inputTextBox_KeyPress(Object^ sender, KeyPressEventArgs^ e)
        {
            if ((e->KeyChar >= '0') && (e->KeyChar <= '9'))
            {
                MessageBox::Show("Control.KeyPress: '" +
                    e->KeyChar.ToString() + "' pressed.");

                switch (e->KeyChar)
                {
                case '2':
                case '5':
                case '8':
                    MessageBox::Show("Control.KeyPress: '" +
                        e->KeyChar.ToString() + "' consumed.");
                    e->Handled = true;
                    break;
                }
            }
        }
    };
}

[STAThread]
int main()
{
    Application::EnableVisualStyles();
    Application::Run(gcnew KeyboardInputForm::Form1());
}

using System;
using System.Drawing;
using System.Windows.Forms;

namespace KeyboardInputForm
{
    class Form1 : Form
    {
        TextBox TextBox1 = new TextBox();

        [STAThread]
        public static void Main()
        {
            Application.EnableVisualStyles();
            Application.Run(new Form1());
        }

        public Form1()
        {
            this.AutoSize = true;

            FlowLayoutPanel panel = new FlowLayoutPanel();
            panel.AutoSize = true;
            panel.FlowDirection = FlowDirection.TopDown;
            panel.Controls.Add(TextBox1);
            this.Controls.Add(panel);

            this.KeyPreview = true;
            this.KeyPress +=
                new KeyPressEventHandler(Form1_KeyPress);
            TextBox1.KeyPress +=
                new KeyPressEventHandler(TextBox1_KeyPress);
        }

        // Detect all numeric characters at the form level and consume 1,
        // 4, and 7. Note that Form.KeyPreview must be set to true for this
        // event handler to be called.
        void Form1_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar >= 48 && e.KeyChar <= 57)
            {
                MessageBox.Show("Form.KeyPress: '" +
                    e.KeyChar.ToString() + "' pressed.");

                switch (e.KeyChar)
                {
                    case (char)49:
                    case (char)52:
                    case (char)55:
                        MessageBox.Show("Form.KeyPress: '" +
                            e.KeyChar.ToString() + "' consumed.");
                        e.Handled = true;
                        break;
                }
            }
        }

        // Detect all numeric characters at the TextBox level and consume
        // 2, 5, and 8.
        void TextBox1_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar >= 48 && e.KeyChar <= 57)
            {
                MessageBox.Show("Control.KeyPress: '" +
                    e.KeyChar.ToString() + "' pressed.");

                switch (e.KeyChar)
                {
                    case (char)50:
                    case (char)53:
                    case (char)56:
                        MessageBox.Show("Control.KeyPress: '" +
                            e.KeyChar.ToString() + "' consumed.");
                        e.Handled = true;
                        break;
                }
            }
        }
    }
}

Imports System.Drawing
Imports System.Windows.Forms

Namespace KeyboardInputForm

     Class Form1
      Inherits Form

        Private WithEvents TextBox1 As New TextBox()

      <STAThread()> _
      Public Shared Sub Main()
         Application.EnableVisualStyles()
         Application.Run(New Form1())
      End Sub

      Public Sub New()
         Me.AutoSize = True

         Dim panel As New FlowLayoutPanel()
         panel.AutoSize = True
         panel.FlowDirection = FlowDirection.TopDown
         panel.Controls.Add(TextBox1)
         Me.Controls.Add(panel)

         Me.KeyPreview = True
        End Sub

        ' Detect all numeric characters at the form level and consume 1, 
        ' 4, and 7. Note that Form.KeyPreview must be set to true for this
        ' event handler to be called.
        Sub Form1_KeyPress(ByVal sender As Object, _
            ByVal e As KeyPressEventArgs) Handles Me.KeyPress

            If e.KeyChar >= ChrW(48) And e.KeyChar <= ChrW(57) Then
                MessageBox.Show(("Form.KeyPress: '" + _
                    e.KeyChar.ToString() + "' pressed."))

                Select Case e.KeyChar
                    Case ChrW(49), ChrW(52), ChrW(55)
                        MessageBox.Show(("Form.KeyPress: '" + _
                            e.KeyChar.ToString() + "' consumed."))
                        e.Handled = True
                End Select
            End If
        End Sub

      ' Detect all numeric characters at the TextBox level and consume  
      ' 2, 5, and 8.
      Sub TextBox1_KeyPress(ByVal sender As Object, _
          ByVal e As KeyPressEventArgs) Handles TextBox1.KeyPress

         If e.KeyChar >= ChrW(48) And e.KeyChar <= ChrW(57) Then
            MessageBox.Show(("Control.KeyPress: '" + _
                e.KeyChar.ToString() + "' pressed."))

            Select Case e.KeyChar
               Case ChrW(50), ChrW(53), ChrW(56)
                  MessageBox.Show(("Control.KeyPress: '" + _
                      e.KeyChar.ToString() + "' consumed."))
                  e.Handled = True
            End Select
         End If
      End Sub

   End Class
End Namespace

Kod Derleniyor

Bu örnek şunları gerektirir:

System, System.Drawing ve System.Windows.Forms derlemelerine başvurular.

Ayrıca bkz.

Bir Windows Forms Uygulamasında Klavye Girdisi

Aracılığıyla paylaş

Nasıl yapılır: Klavye Girdisini Form Düzeyinde İşleme

Bir klavye iletisini form düzeyinde işlemek için

Örnek

Kod Derleniyor

Ayrıca bkz.

Ek kaynaklar