70-526 MCTS

• BorderColor - Gets or sets the color of the border around the button.
• BorderSize - Gets or sets a value that specifies the size, in pixels, of the border around the button.
• MouseDownBackColor - Gets or sets the color of the client area of the button when the mouse is pressed within the bounds of the control.
• MouseOverBackColor - Gets or sets the color of the client area of the button when the mouse pointer is within the bounds of the control.

• Flat - The control appears flat until the mouse pointer moves over it, at which point it becomes highlighted.
• Popup - A control appears flat until the mouse pointer moves over it, at which point it appears three-dimensional.
• Standard - The control appears three-dimensional (default).
• System - The appearance of the control is determined by the user's operating system.

• BottomCenter - Content is vertically aligned at the bottom, and horizontally aligned at the center.
• BottomLeft - Content is vertically aligned at the bottom, and horizontally aligned on the left.
• BottomRight - Content is vertically aligned at the bottom, and horizontally aligned on the right.
• MiddleCenter - Content is vertically aligned in the middle, and horizontally aligned at the center (default).
• MiddleLeft - Content is vertically aligned in the middle, and horizontally aligned on the left.
• MiddleRight - Content is vertically aligned in the middle, and horizontally aligned on the right.
• TopCenter - Content is vertically aligned at the top, and horizontally aligned at the center.
• TopLeft - Content is vertically aligned at the top, and horizontally aligned on the left.
• TopRight - Content is vertically aligned at the top, and horizontally aligned on the right.

• ImageAboveText - Specifies that the image is displayed vertically above the text of a control.
• ImageBeforeText - Specifies that the image is displayed horizontally before the text of a control.
• Overlay - Specifies that the image and text share the same space on a control (default).
• TextAboveImage - Specifies that the text is displayed vertically above the image of a control.
• TextBeforeImage - Specifies that the text is displayed horizontally before the image of a control.

The Click Event

The Click event responds to either the left mouse button being clicked whilst hovering over the button, or the ENTER key being pressed when the button has focus. This event passes an EventArgs parameter to its event handler, so it only indicates that a click has occurred. An event handler for the event can be added in the following way.

In the Designer window, double-click on the button that you wish to handle the Click event for. The IDE causes two things to happen in the code behind the form. First of all, a subscription to the event is created in the InitializeComponent() method:

this.button1.Click += new System.EventHandler(this.button1_Click);

The second thing that happens, is that the event handler itself is added:

private void button1_Click(object sender, EventArgs e)
{
   this.Text = "Hello";
}

The method name that is created by the IDE is a concatenation of the name of the control, an underscore and the name of the event that is being handled. The EventArgs parameter holds information about what occured.

Events are described in more depth in section 1-5.

Determining Clicks

Another event that often needs to be responded to is the MouseDown event. This event occurs whenever any of the mouse buttons are clicked. To determine which button has been pressed the MouseEventArgs parameter can be interrogated.

Rhe MouseEventArgs class has the following Public properties

• Left - The left mouse button was pressed.
• Middle - The middle mouse button was pressed.
• None - No mouse button was pressed.
• Right - The right mouse button was pressed.
• XButton1 - The first XButton was pressed.
• XButton2 - The second XButton was pressed.
  
  With Windows 2000, Microsoft is introducing support for the Microsoft IntelliMouse Explorer, which is a mouse with five buttons. The two new mouse buttons (XBUTTON1 and XBUTTON2) provide backward/forward navigation.

Using the values exposed in the Button property, the button that was pressed can be determined.

1. Select the button in the Design window.

2. In the properties window, click on the lightning bolt, to bring up the events window.

3. Double click in the cell next to the MouseDown event. The IDE will generate the skeleton code to handle this event.

4. In the event handler, add the following code

   private void button1_MouseDown(object sender, MouseEventArgs e)
   {
     string eventString = null;
     switch (e.Button)
     {
       case MouseButtons.Left:
         eventString = "L";
       break;
   
       case MouseButtons.Right:
         eventString = "R";
       break;
   
       case MouseButtons.Middle:
         eventString = "M";
       break;
   
       case MouseButtons.XButton1:
         eventString = "X1";
       break;
   
       case MouseButtons.XButton2:
         eventString = "X2";
       break;
   
       case MouseButtons.None:
       default:
       break;
     }
   }

Handling DialogResult

The DialogResult property value that is returned to the parent form when the button is clicked can be used to determine when a form is closing and how it had been closed. This can be seen in action with a demonstration.

1. Open a new windows application. Drag a button and a label onto the form.

2. Set the text of the button to "Click Me" and the text of the label to "".

3. Add a second form to the application named NameFrm.

4. Set up the second form as per the following.
   

5. Make the textbox Public. (Keeps things simple but this is a bad practice).

6. Set the DialogResult property of the OK button to OK.

7. Set the DialogResult property of the Cancel button to Cancel.

8. Add the following code to the button event handler of the first form.

   private void button1_Click(object sender, EventArgs e)
   {
     NameFrm aName = new NameFrm();
   
     if (aName.ShowDialog() == DialogResult.OK)
     {
       this.label1.Text = "Hello " + aName.textBox1.Text;
     }
   }

   The label only changes if the OK button is pressed.

9. Run the app.

To demonstrate this further, this sample application (written in C# Express) is the completed sample for above.

MSDN references