Appendix A : Useful Control Properties, Methods, and Events


A control interacts with a program or the user through properties, methods, and events. Although each type of control provides different features, they are all derived from the Control class. This class provides many useful properties, methods, and events that other controls inherit, if they don’t take special action to override them. The following sections describe some of the most useful of these inherited features.

Properties

The following table lists properties implemented by the Control class. All controls that inherit from this class inherit these properties unless they override the Control class’s behavior.

Open table as spreadsheet

Property

Purpose

AllowDrop

Determines whether the control allows drag-and-drop operations.

Anchor

Determines which of the control’s edges are anchored to the edges of the control’s container.

AutoSize

Determines whether the control automatically resizes to fit its contents.

BackColor

Determines the control’s background color.

BackgroundImage

Determines the control’s background image.

BackgroundImageLayout

Determines how the control’s background image is used to fill the control. This can be Center, None, Tile, Stretch, and Zoom.

Bottom

Returns the distance between the top edge of the control’s container and the bottom edge of the control. This is read-only. Modify the Top and Height properties to change this value.

Bounds

Determines the control’s size and location, including nonclient areas.

CanFocus

Determines whether the control can receive the input focus. See also the Focus method.

CanSelect

Determines whether the control can select. For example, a TextBox can select some or all of its text. See also the Select method.

Capture

Determines whether the control has captured the mouse.

CausesValidation

Determines whether the control makes other controls validate when it receives the focus.

ClientRectangle

This Rectangle structure represents the control’s client area.

ClientSize

This Size structure represents the control’s height and width.

ContainsFocus

Indicates whether the control or one of its child controls has the input focus. This is read-only.

ContextMenu

Determines the context menu associated with the control.

ContextMenuStrip

Determines the context menu strip associated with the control.

Controls

This collection contains references to the controls contained within this control.

Cursor

Determines the cursor that the control displays when the mouse is over it.

DataBindings

Gets the control’s DataBindings, used to bind the control to a data source.

DefaultBackColor

Returns the control’s default background color.

DefaultFont

Returns the control’s default font.

DefaultForeColor

Returns the control’s default foreground color.

DisplayRectangle

Returns a Rectangle structure giving the control’s display area. Figure A-1 shows two GroupBoxes containing two Labels each. The Labels in the left GroupBox show the ClientRectangle (Label1) and DisplayRectangle (Label2) of the GroupBox.

Dock

Determines the edge of the control’s parent to which the control is docked.

Enabled

Determines whether the control will interact with the user.

Focused

Indicates whether the control has the input focus. This is read-only.

Font

Determines the control’s font.

ForeColor

Determines the control’s foreground color.

Handle

Returns the control’s window handle. This is read-only.

HasChildren

Indicates whether the control holds any child controls. This is read-only. Also see the Controls property.

Height

Determines the control’s height.

InvokeRequired

Returns True if the calling code is running on a thread different from the control’s thread and therefore must use an invoke method to interact with the control.

Left

Determines the X coordinate of the control’s left edge.

Location

This Point structure determines the position of the control’s upper-left corner.

Margin

Determines the spacing between this control and another control’s margin within an arranging container.

MaximumSize

Determines the control’s largest allowed size.

MinimumSize

Determines the control’s smallest allowed size.

ModifierKeys

Indicates what modifier keys (Shift, Ctrl, and Alt) are pressed. This is read-only.

MouseButtons

Indicates what mouse buttons (Left, Right, Middle, None) are pressed. This is read-only.

MousePosition

Returns a Point structure giving the mouse’s current position in screen coordinates (the point (0, 0) is in the screen’s upper-left corner). This is read-only.

Name

Determines the control’s name.

Padding

Determines the spacing of the control’s contents.

Parent

Determines the parent containing the control.

PreferredSize

Returns a size that is big enough to hold the control’s contents.

Region

Determines the control’s window region. This is the area in which the control may draw.

Right

Returns the distance between the left edge of the control’s container and the right edge of the control. This is read-only. Modify the Left and Width properties to change this value.

Size

This Size structure determines the control’s size including client and nonclient areas.

TabIndex

Determines the control’s position in its container’s tab order. If more than one control has the same TabIndex, they are traversed front to back using the stacking order.

TabStop

Determines whether the user can tab to the control.

Tag

This property can hold an object that you want to associate with the control.

Text

Determines the control’s text.

Top

Determines the Y coordinate of the control’s top edge.

TopLevelControl

Returns the control’s top-level ancestor. Usually that is the outermost Form containing the control. This is read-only.

Visible

Determines whether the control is visible.

Width

Determines the control’s width.

image from book
Figure A-1: The DisplayRectangle property gives the area in which you should normally place items within a control.




Visual Basic 2005 with  .NET 3.0 Programmer's Reference
Visual Basic 2005 with .NET 3.0 Programmer's Reference
ISBN: 470137053
EAN: N/A
Year: 2007
Pages: 417

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