Практическое руководство. Обработка событий пользовательского ввода в элементах управления Windows Forms
В этом примере демонстрируется, как обрабатывать большинство событий клавиатуры, мыши, фокуса и проверки, которые происходят в элементе управления Windows Forms. Текстовое поле с именем TextBoxInput получает события при установке в нем фокуса, и сведения о каждом событии записываются в текстовое поле с именем TextBoxOutput в том порядке, в котором вызываются события. В приложении также есть набор флажков, с помощью которых можно фильтровать события, о которых нужно сообщать.
Пример
using System;
using System.Drawing;
using System.ComponentModel;
using System.Windows.Forms;
namespace UserInputWalkthrough
{
public class Form1 : Form
{
Label Label1 = new Label();
Label Label2 = new Label();
TextBox TextBoxOutput = new TextBox();
TextBox TextBoxInput = new TextBox();
GroupBox GroupBoxEvents = new GroupBox();
Button ButtonClear = new Button();
LinkLabel LinkLabelDrag = new LinkLabel();
CheckBox CheckBoxToggleAll = new CheckBox();
CheckBox CheckBoxMouse = new CheckBox();
CheckBox CheckBoxMouseEnter = new CheckBox();
CheckBox CheckBoxMouseMove = new CheckBox();
CheckBox CheckBoxMousePoints = new CheckBox();
CheckBox CheckBoxMouseDrag = new CheckBox();
CheckBox CheckBoxMouseDragOver = new CheckBox();
CheckBox CheckBoxKeyboard = new CheckBox();
CheckBox CheckBoxKeyUpDown = new CheckBox();
CheckBox CheckBoxFocus = new CheckBox();
CheckBox CheckBoxValidation = new CheckBox();
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.Run(new Form1());
}
public Form1()
: base()
{
this.Load += new EventHandler(Form1_Load);
}
private void Form1_Load(object sender, EventArgs e)
{
this.GroupBoxEvents.SuspendLayout();
this.SuspendLayout();
Label1.Location = new Point(232, 12);
Label1.Size = new Size(98, 14);
Label1.AutoSize = true;
Label1.Text = "Generated Events:";
Label2.Location = new Point(13, 12);
Label2.Size = new Size(95, 14);
Label2.AutoSize = true;
Label2.Text = "User Input Target:";
TextBoxInput.Location = new Point(13, 34);
TextBoxInput.Size = new Size(200, 200);
TextBoxInput.AllowDrop = true;
TextBoxInput.AutoSize = false;
TextBoxInput.Cursor = Cursors.Cross;
TextBoxInput.Multiline = true;
TextBoxInput.TabIndex = 1;
LinkLabelDrag.AllowDrop = true;
LinkLabelDrag.AutoSize = true;
LinkLabelDrag.Location = new Point(13, 240);
LinkLabelDrag.Size = new Size(175, 14);
LinkLabelDrag.TabIndex = 2;
LinkLabelDrag.TabStop = true;
LinkLabelDrag.Text = "Click here to use as a drag source";
LinkLabelDrag.Links.Add(new LinkLabel.Link(0,
LinkLabelDrag.Text.Length));
GroupBoxEvents.Location = new Point(13, 281);
GroupBoxEvents.Size = new Size(200, 302);
GroupBoxEvents.Text = "Event Filter:";
GroupBoxEvents.TabStop = true;
GroupBoxEvents.TabIndex = 3;
GroupBoxEvents.Controls.Add(CheckBoxMouseEnter);
GroupBoxEvents.Controls.Add(CheckBoxToggleAll);
GroupBoxEvents.Controls.Add(CheckBoxMousePoints);
GroupBoxEvents.Controls.Add(CheckBoxKeyUpDown);
GroupBoxEvents.Controls.Add(CheckBoxMouseDragOver);
GroupBoxEvents.Controls.Add(CheckBoxMouseDrag);
GroupBoxEvents.Controls.Add(CheckBoxValidation);
GroupBoxEvents.Controls.Add(CheckBoxMouseMove);
GroupBoxEvents.Controls.Add(CheckBoxFocus);
GroupBoxEvents.Controls.Add(CheckBoxKeyboard);
GroupBoxEvents.Controls.Add(CheckBoxMouse);
CheckBoxToggleAll.AutoSize = true;
CheckBoxToggleAll.Location = new Point(7, 20);
CheckBoxToggleAll.Size = new Size(122, 17);
CheckBoxToggleAll.TabIndex = 4;
CheckBoxToggleAll.Text = "Toggle All Events";
CheckBoxMouse.AutoSize = true;
CheckBoxMouse.Location = new Point(7, 45);
CheckBoxMouse.Size = new Size(137, 17);
CheckBoxMouse.TabIndex = 5;
CheckBoxMouse.Text = "Mouse and Click Events";
CheckBoxMouseEnter.AutoSize = true;
CheckBoxMouseEnter.Location = new Point(26, 69);
CheckBoxMouseEnter.Margin = new Padding(3, 3, 3, 1);
CheckBoxMouseEnter.Size = new System.Drawing.Size(151, 17);
CheckBoxMouseEnter.TabIndex = 6;
CheckBoxMouseEnter.Text = "Mouse Enter/Hover/Leave";
CheckBoxMouseMove.AutoSize = true;
CheckBoxMouseMove.Location = new Point(26, 89);
CheckBoxMouseMove.Margin = new Padding(3, 2, 3, 3);
CheckBoxMouseMove.Size = new Size(120, 17);
CheckBoxMouseMove.TabIndex = 7;
CheckBoxMouseMove.Text = "Mouse Move Events";
CheckBoxMousePoints.AutoSize = true;
CheckBoxMousePoints.Location = new Point(26, 112);
CheckBoxMousePoints.Margin = new Padding(3, 3, 3, 1);
CheckBoxMousePoints.Size = new Size(141, 17);
CheckBoxMousePoints.TabIndex = 8;
CheckBoxMousePoints.Text = "Draw Mouse Points";
CheckBoxMouseDrag.AutoSize = true;
CheckBoxMouseDrag.Location = new Point(26, 135);
CheckBoxMouseDrag.Margin = new Padding(3, 1, 3, 3);
CheckBoxMouseDrag.Size = new Size(151, 17);
CheckBoxMouseDrag.TabIndex = 9;
CheckBoxMouseDrag.Text = "Mouse Drag && Drop Events";
CheckBoxMouseDragOver.AutoSize = true;
CheckBoxMouseDragOver.Location = new Point(44, 159);
CheckBoxMouseDragOver.Size = new Size(142, 17);
CheckBoxMouseDragOver.TabIndex = 10;
CheckBoxMouseDragOver.Text = "Mouse Drag Over Events";
CheckBoxKeyboard.AutoSize = true;
CheckBoxKeyboard.Location = new Point(8, 184);
CheckBoxKeyboard.Size = new Size(103, 17);
CheckBoxKeyboard.TabIndex = 11;
CheckBoxKeyboard.Text = "Keyboard Events";
CheckBoxKeyUpDown.AutoSize = true;
CheckBoxKeyUpDown.Location = new Point(26, 207);
CheckBoxKeyUpDown.Margin = new Padding(3, 3, 3, 1);
CheckBoxKeyUpDown.Size = new Size(133, 17);
CheckBoxKeyUpDown.TabIndex = 12;
CheckBoxKeyUpDown.Text = "Key Up && Down Events";
CheckBoxFocus.AutoSize = true;
CheckBoxFocus.Location = new Point(8, 233);
CheckBoxFocus.Margin = new Padding(3, 2, 3, 3);
CheckBoxFocus.Size = new Size(146, 17);
CheckBoxFocus.TabIndex = 13;
CheckBoxFocus.Text = "Focus && Activation Events";
CheckBoxValidation.AutoSize = true;
CheckBoxValidation.Location = new Point(8, 257);
CheckBoxValidation.Size = new Size(104, 17);
CheckBoxValidation.TabIndex = 14;
CheckBoxValidation.Text = "Validation Events";
TextBoxOutput.Location = new Point(232, 34);
TextBoxOutput.Size = new Size(308, 510);
TextBoxOutput.Multiline = true;
TextBoxOutput.CausesValidation = false;
TextBoxOutput.ReadOnly = true;
TextBoxOutput.ScrollBars = ScrollBars.Vertical;
TextBoxOutput.TabIndex = 15;
TextBoxOutput.WordWrap = false;
ButtonClear.Location = new Point(232, 560);
ButtonClear.Size = new Size(308, 23);
ButtonClear.TabIndex = 16;
ButtonClear.Text = "Clear Event List";
this.ClientSize = new Size(552, 595);
this.Controls.Add(LinkLabelDrag);
this.Controls.Add(ButtonClear);
this.Controls.Add(GroupBoxEvents);
this.Controls.Add(Label1);
this.Controls.Add(Label2);
this.Controls.Add(TextBoxInput);
this.Controls.Add(TextBoxOutput);
this.Text = "User Input Events";
ButtonClear.Click +=
new EventHandler(ButtonClear_Click);
TextBoxInput.KeyDown +=
new KeyEventHandler(TextBoxInput_KeyDown);
TextBoxInput.KeyPress +=
new KeyPressEventHandler(TextBoxInput_KeyPress);
TextBoxInput.KeyUp +=
new KeyEventHandler(TextBoxInput_KeyUp);
TextBoxInput.Click +=
new EventHandler(TextBoxInput_Click);
TextBoxInput.DoubleClick +=
new EventHandler(TextBoxInput_DoubleClick);
TextBoxInput.MouseClick +=
new MouseEventHandler(TextBoxInput_MouseClick);
TextBoxInput.MouseDoubleClick +=
new MouseEventHandler(TextBoxInput_MouseDoubleClick);
TextBoxInput.MouseDown +=
new MouseEventHandler(TextBoxInput_MouseDown);
TextBoxInput.MouseUp +=
new MouseEventHandler(TextBoxInput_MouseUp);
TextBoxInput.MouseEnter +=
new EventHandler(TextBoxInput_MouseEnter);
TextBoxInput.MouseHover +=
new EventHandler(TextBoxInput_MouseHover);
TextBoxInput.MouseLeave +=
new EventHandler(TextBoxInput_MouseLeave);
TextBoxInput.MouseWheel +=
new MouseEventHandler(TextBoxInput_MouseWheel);
TextBoxInput.MouseMove +=
new MouseEventHandler(TextBoxInput_MouseMove);
TextBoxInput.MouseCaptureChanged +=
new EventHandler(TextBoxInput_MouseCaptureChanged);
TextBoxInput.DragEnter +=
new DragEventHandler(TextBoxInput_DragEnter);
TextBoxInput.DragDrop +=
new DragEventHandler(TextBoxInput_DragDrop);
TextBoxInput.DragOver +=
new DragEventHandler(TextBoxInput_DragOver);
TextBoxInput.DragLeave +=
new EventHandler(TextBoxInput_DragLeave);
TextBoxInput.Enter +=
new EventHandler(TextBoxInput_Enter);
TextBoxInput.Leave +=
new EventHandler(TextBoxInput_Leave);
TextBoxInput.GotFocus +=
new EventHandler(TextBoxInput_GotFocus);
TextBoxInput.LostFocus +=
new EventHandler(TextBoxInput_LostFocus);
TextBoxInput.Validated +=
new EventHandler(TextBoxInput_Validated);
TextBoxInput.Validating +=
new CancelEventHandler(TextBoxInput_Validating);
LinkLabelDrag.MouseDown +=
new MouseEventHandler(LinkLabelDrag_MouseDown);
LinkLabelDrag.GiveFeedback +=
new GiveFeedbackEventHandler(LinkLabelDrag_GiveFeedback);
CheckBoxToggleAll.CheckedChanged +=
new EventHandler(CheckBoxToggleAll_CheckedChanged);
CheckBoxMouse.CheckedChanged +=
new EventHandler(CheckBoxMouse_CheckedChanged);
CheckBoxMouseDrag.CheckedChanged +=
new EventHandler(CheckBoxMouseDrag_CheckedChanged);
CheckBoxMouseEnter.CheckedChanged +=
new EventHandler(CheckBoxMouseMove_CheckedChanged);
CheckBoxMouseMove.CheckedChanged +=
new EventHandler(CheckBoxMouseMove_CheckedChanged);
CheckBoxKeyboard.CheckedChanged +=
new EventHandler(CheckBoxKeyboard_CheckedChanged);
this.GroupBoxEvents.ResumeLayout(false);
this.GroupBoxEvents.PerformLayout();
this.ResumeLayout(false);
this.PerformLayout();
CheckAllChildCheckBoxes(this, true);
}
// Recursively search the form for all contained checkboxes and
// initially check them
private void CheckAllChildCheckBoxes(Control parent, bool value)
{
CheckBox box;
foreach (Control currentControl in parent.Controls)
{
if (currentControl is CheckBox)
{
box = (CheckBox)currentControl;
box.Checked = value;
}
// Recurse if control contains other controls
if (currentControl.Controls.Count > 0)
{
CheckAllChildCheckBoxes(currentControl, value);
}
}
}
// All-purpose method for displaying a line of text in the
// text boxe.
private void DisplayLine(string line)
{
TextBoxOutput.AppendText(line);
TextBoxOutput.AppendText(Environment.NewLine);
}
// Click event handler for the button that clears the text box.
private void ButtonClear_Click(object sender, EventArgs e)
{
TextBoxOutput.Invalidate();
TextBoxOutput.Clear();
}
private void TextBoxInput_KeyDown(object sender, KeyEventArgs e)
{
if (CheckBoxKeyUpDown.Checked)
{
DisplayLine("KeyDown: " + e.KeyData.ToString());
}
}
private void TextBoxInput_KeyUp(object sender, KeyEventArgs e)
{
if (CheckBoxKeyUpDown.Checked)
{
DisplayLine("KeyUp: " + e.KeyData.ToString());
}
}
private void TextBoxInput_KeyPress(object sender,
KeyPressEventArgs e)
{
if (CheckBoxKeyboard.Checked)
{
if (Char.IsWhiteSpace(e.KeyChar))
{
DisplayLine("KeyPress: WS");
}
else
{
DisplayLine("KeyPress: " + e.KeyChar.ToString());
}
}
}
private void TextBoxInput_Click(object sender, EventArgs e)
{
if (CheckBoxMouse.Checked)
{
DisplayLine("Click event");
}
}
private void TextBoxInput_DoubleClick(object sender, EventArgs e)
{
if (CheckBoxMouse.Checked)
{
DisplayLine("DoubleClick event");
}
}
private void TextBoxInput_MouseClick(object sender, MouseEventArgs e)
{
if (CheckBoxMouse.Checked)
{
DisplayLine("MouseClick: " + e.Button.ToString() +
" " + e.Location.ToString());
}
}
private void TextBoxInput_MouseDoubleClick(object sender,
MouseEventArgs e)
{
if (CheckBoxMouse.Checked)
{
DisplayLine("MouseDoubleClick: " + e.Button.ToString() +
" " + e.Location.ToString());
}
}
private void TextBoxInput_MouseDown(object sender,
MouseEventArgs e)
{
if (CheckBoxMouse.Checked)
{
DisplayLine("MouseDown: " + e.Button.ToString() +
" " + e.Location.ToString());
}
}
private void TextBoxInput_MouseUp(object sender,
MouseEventArgs e)
{
if (CheckBoxMouse.Checked)
{
DisplayLine("MouseUp: " + e.Button.ToString() +
" " + e.Location.ToString());
}
// The TextBox control was designed to change focus only on
// the primary click, so force focus to avoid user confusion.
if (!TextBoxInput.Focused)
{
TextBoxInput.Focus();
}
}
private void TextBoxInput_MouseEnter(object sender, EventArgs e)
{
if (CheckBoxMouseEnter.Checked)
{
DisplayLine("MouseEnter event");
}
}
private void TextBoxInput_MouseHover(object sender, EventArgs e)
{
if (CheckBoxMouseEnter.Checked)
{
DisplayLine("MouseHover event");
}
}
private void TextBoxInput_MouseLeave(object sender, EventArgs e)
{
if (CheckBoxMouseEnter.Checked)
{
DisplayLine("MouseLeave event");
}
}
private void TextBoxInput_MouseWheel(object sender,
MouseEventArgs e)
{
if (CheckBoxMouse.Checked)
{
DisplayLine("MouseWheel: " + e.Delta.ToString() +
" detents at " + e.Location.ToString());
}
}
private void TextBoxInput_MouseMove(object sender,
MouseEventArgs e)
{
if (CheckBoxMouseMove.Checked)
{
DisplayLine("MouseMove: " + e.Button.ToString() + " " +
e.Location.ToString());
}
if (CheckBoxMousePoints.Checked)
{
Graphics g = TextBoxInput.CreateGraphics();
g.FillRectangle(Brushes.Black, e.Location.X,
e.Location.Y, 1, 1);
g.Dispose();
}
}
private void TextBoxInput_MouseCaptureChanged(object sender,
EventArgs e)
{
if (CheckBoxMouseDrag.Checked)
{
DisplayLine("MouseCaptureChanged event");
}
}
private void TextBoxInput_DragEnter(object sender,
DragEventArgs e)
{
if (CheckBoxMouseDrag.Checked)
{
Point pt = new Point(e.X, e.Y);
DisplayLine("DragEnter: " +
CovertKeyStateToString(e.KeyState)
+ " at " + pt.ToString());
}
}
private void TextBoxInput_DragDrop(object sender,
DragEventArgs e)
{
if (CheckBoxMouseDrag.Checked)
{
Point pt = new Point(e.X, e.Y);
DisplayLine("DragDrop: " +
CovertKeyStateToString(e.KeyState)
+ " at " + pt.ToString());
}
}
private void TextBoxInput_DragOver(object sender,
DragEventArgs e)
{
if (CheckBoxMouseDragOver.Checked)
{
Point pt = new Point(e.X, e.Y);
DisplayLine("DragOver: " +
CovertKeyStateToString(e.KeyState)
+ " at " + pt.ToString());
}
// Allow if drop data is of type string.
if (!e.Data.GetDataPresent(typeof(String)))
{
e.Effect = DragDropEffects.None;
}
else
{
e.Effect = DragDropEffects.Copy;
}
}
private void TextBoxInput_DragLeave(object sender,
EventArgs e)
{
if (CheckBoxMouseDrag.Checked)
{
DisplayLine("DragLeave event");
}
}
private string CovertKeyStateToString(int keyState)
{
string keyString = "None";
// Which button was pressed?
if ((keyState & 1) == 1)
{
keyString = "Left";
}
else if ((keyState & 2) == 2)
{
keyString = "Right";
}
else if ((keyState & 16) == 16)
{
keyString = "Middle";
}
// Are one or more modifier keys also pressed?
if ((keyState & 4) == 4)
{
keyString += "+SHIFT";
}
if ((keyState & 8) == 8)
{
keyString += "+CTRL";
}
if ((keyState & 32) == 32)
{
keyString += "+ALT";
}
return keyString;
}
private void TextBoxInput_Enter(object sender, EventArgs e)
{
if (CheckBoxFocus.Checked)
{
DisplayLine("Enter event");
}
}
private void TextBoxInput_Leave(object sender, EventArgs e)
{
if (CheckBoxFocus.Checked)
{
DisplayLine("Leave event");
}
}
private void TextBoxInput_GotFocus(object sender, EventArgs e)
{
if (CheckBoxFocus.Checked)
{
DisplayLine("GotFocus event");
}
}
private void TextBoxInput_LostFocus(object sender, EventArgs e)
{
if (CheckBoxFocus.Checked)
{
DisplayLine("LostFocus event");
}
}
private void TextBoxInput_Validated(object sender, EventArgs e)
{
if (CheckBoxValidation.Checked)
{
DisplayLine("Validated event");
}
}
private void TextBoxInput_Validating(
object sender, CancelEventArgs e)
{
if (CheckBoxValidation.Checked)
{
DisplayLine("Validating event");
}
}
private void CheckBoxToggleAll_CheckedChanged(
object sender, EventArgs e)
{
if (sender is CheckBox)
{
CheckAllChildCheckBoxes(this, ((CheckBox)sender).Checked);
}
}
private void CheckBoxMouse_CheckedChanged(
object sender, EventArgs e)
{
ConfigureCheckBoxSettings();
}
private void CheckBoxMouseDrag_CheckedChanged(
object sender, EventArgs e)
{
ConfigureCheckBoxSettings();
}
private void CheckBoxKeyboard_CheckedChanged(
object sender, EventArgs e)
{
ConfigureCheckBoxSettings();
}
private void CheckBoxMouseMove_CheckedChanged(
object sender, EventArgs e)
{
ConfigureCheckBoxSettings();
}
// Reconcile dependencies between the check box
// selection choices.
private void ConfigureCheckBoxSettings()
{
// CheckBoxMouse is a top-level check box.
if (!CheckBoxMouse.Checked)
{
CheckBoxMouseEnter.Enabled = false;
CheckBoxMouseMove.Enabled = false;
CheckBoxMouseDrag.Enabled = false;
CheckBoxMouseDragOver.Enabled = false;
CheckBoxMousePoints.Enabled = false;
}
else
{
CheckBoxMouseEnter.Enabled = true;
CheckBoxMouseMove.Enabled = true;
CheckBoxMouseDrag.Enabled = true;
CheckBoxMousePoints.Enabled = true;
// Enable children depending on the state of the parent.
if (!CheckBoxMouseDrag.Checked)
{
CheckBoxMouseDragOver.Enabled = false;
}
else
{
CheckBoxMouseDragOver.Enabled = true;
}
}
if (!CheckBoxKeyboard.Checked)
{
CheckBoxKeyUpDown.Enabled = false;
}
else
{
CheckBoxKeyUpDown.Enabled = true;
}
}
private void LinkLabelDrag_MouseDown(object sender,
MouseEventArgs e)
{
string data = "Sample Data";
LinkLabelDrag.DoDragDrop(data, DragDropEffects.All);
}
private void LinkLabelDrag_GiveFeedback(object sender,
GiveFeedbackEventArgs e)
{
if ((e.Effect & DragDropEffects.Copy) ==
DragDropEffects.Copy)
{
LinkLabelDrag.Cursor = Cursors.HSplit;
}
else
{
LinkLabelDrag.Cursor = Cursors.Default;
}
}
}
}
Компиляция кода
Для этого примера требуются:
- ссылки на сборки System, System.Drawing и System.Windows.Forms.
Сведения о выполнении сборки этого примера из командной строки для Visual Basic или Visual C#, см. в разделе построение из командной строки или командной строки создания с помощью csc.exe. Можно также сборке этого примера в Visual Studio путем вставки кода в новый проект.