Component Button. Interaction between Label and Button components. The MouseMove event

Before studying this topic, it is recommended that you familiarize yourself with the previous topic:

• The Label component. Programmatic creation of the Label component. The MessageBox class. The DialogResult enum

Contents

• 1. General information about the Button component
• 2. Properties of Button component
• 3. Events of the Button control
• 4. An example of using the Label and Button components. Programming the MouseMove event
  • 4.1. Task
  • 4.2. Instructions
    • 4.2.1. Project creation
    • 4.2.2. Placement of Label, Button controls. Customizing controls
    • 4.2.3. Programming the Click event of the button1 component. Get the size of the form
    • 4.2.4. Programming the Click event of the button2 component. Show or hide form components
    • 4.2.5. Programming the MouseMove event handler for the label2 component
• Related topics

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1. General information about the Button component

The Button component is a button on the form (Figure 1).

Figure 1. Component Button. Placement in Toolbox

The Button component is a class that inherits from the ButtonCase abstract class and implements the IButtonControl interface. In turn, the ButtonCase class is inherited from the Control class. In many .NET Framework classes, there are 3 types of buttons that inherit from ButtonCase: Button, CheckBox, RadioButton.

The Button class (component) has a set of properties available both programmatically and in design mode (Figure 2).

Figure 2. Properties of Button component

Following are the main properties of the Button component.

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2. Properties of Button component

The basic properties of the Button control are given below. Here are the basic properties that are different from the properties of the Label component. You can read more about the Label component here.

// Declare an instance of type form
Form2 f2 = new Form2();

// If the return result from the form is OK, then perform some actions
if (f2.ShowDialog() == DialogResult.OK)
{
  // actions to be performed if the OK button is pressed
  // ...
}

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3. Events of the Button control

The following table displays the main actions of a Button control.

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4. An example of using the Label and Button components. Programming the MouseMove event

4.1. Task

Develop a project containing 2 buttons (Button) and 2 labels (Label). Investigate the operation of the component by completing the following steps.

4.2. Instructions

4.2.1. Project creation

Create a project using Microsoft Visual Studio. An example of creating a project of the “C# – Windows Forms” type can be found here.

Name the project “Demo Program”. To do this, you can use the Text property of the main form Form1.

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4.2.2. Placement of Label, Button controls. Customizing controls

Place two controls of the Label type and two controls of the Button type on the form. As a result, the system will create four instances named label1, label2, button1, button2 (Figure 3).

Figure 3. Initial state of the form and controls on the form

Set the following properties of form controls:

• label1.Text = “Form Size = “ (the Text property of the label1 control);
• label2.Text = “Catch me!”;
• button1.Text = “Form Size”;
• button2.Text = “Hide/Show”.

After adjusting the size of some controls and settings, the form will look like shown in Figure 4.

Figure 4. Form view after customizing controls

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4.2.3. Programming the Click event of the button1 component. Get the size of the form

At this stage, you need to program the Click event handler of the button1 component. More details about the features of event programming in Microsoft Visual Studio can be found here.

The text of the button1_Click() event handler is as follows:

private void button1_Click(object sender, EventArgs e)
{
  // The click event handler for the button1 button.
  // Display the dimensions of the form, use the Width, Height properties.
  label1.Text = String.Format("Form Size: W = {0}, H = {1}",
    this.Width, this.Height);
}

As you can see from the above code, by pressing the button1 button in the label1 component, information about the current size of the form is displayed. If, while running the program, you try to resize the form and press button1, the new sizes will be displayed again in label1.

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4.2.4. Programming the Click event of the button2 component. Show or hide form components

When button2 (“Show/Hide”) is clicked, label1, label2, button2 components must be hidden or displayed. According to this, in the Click event handler of the button2 component, you must enter the following text

private void button2_Click(object sender, EventArgs e)
{
  // Show/Hide - property Visible
  button1.Visible = !button1.Visible;
  label1.Visible = !label1.Visible;
  label2.Visible = !label2.Visible;

  if (button1.Visible)
    button2.Text = "Hide";
  else
    button2.Text = "Show";
}

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4.2.5. Programming the MouseMove event handler for the label2 component

The MouseMove event of any control occurs when the mouse moves over the rectangular area of that control. The Label type component can also program this event.

In the label2_MouseMove() event handler, the following code is entered

private void label2_MouseMove(object sender, MouseEventArgs e)
{
  // The MouseMove event for the label2 component means that the label needs to be moved

  // 1. Attempt to place area label2
  label2.Left = label2.Left + 10;
  label2.Top = label2.Top - 10;

  // 2. Checking if the label is out of shape at the X coordinate
  if ((label2.Left < -20) || (label2.Left > this.Width - 20))
  {
    // If the label has gone beyond the form along the x coordinate,
    // then change the horizontal position of label2
    label2.Left = 10;
  }

  // 3. Checking if the label is out of the form at the Y coordinate
  if ((label2.Top < -10) || (label2.Top > this.Height - 10))
  {
    // If the label is outside the form in Y coordinate,
    // then change the vertical position of label2
    label2.Top = 80;
  }
}

After starting the program for execution, it will not work to move the mouse inside the rectangular area occupied by label2.

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Related topics

• Creating a pentagonal form
• Example of developing an inherited form
• The Label component. Programmatic creation of the Label component. The MessageBox class. The DialogResult enum

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