C# 4 and .NET 4

standard Controls and Components ❘ 1137
the image is sized and positioned in the control. The SizeMode property can be AutoSize, CenterImage,
Normal, and StretchImage.
You can change the size of the display of the PictureBox by setting the ClientSize property. You load the
PictureBox by first creating an Image-based object. For example, to load a JPEG file into a PictureBox,
you would do the following:
Bitmap myJpeg = Bitmap.FromFile("whatever.png") as Bitmap;
pictureBox1.Image = myJpeg;
Progressbar
The ProgressBar control is a visual clue to the status of a lengthy operation. It indicates to users that there
is something going on and that they should wait. The ProgressBar control works by setting the Minimum
and Maximum properties, which correspond to the progress indicator being all the way to the left (Minimum)
or all the way to the right (Maximum). You set the Step property to determine the number that the value is
incremented each time the PerformStep method is called. You can also use the Increment method and
increment the value by the value passed in the method call. The Value property returns the current value of
the ProgressBar.
Textbox, richTextbox, and maskedTextbox
The TextBox control is one of the most used controls in the toolbox. The TextBox, RichTextBox, and
MaskedTextBox controls are all derived from TextBoxBase. TextBoxBase provides properties such as
MultiLine and Lines. MultiLine is a Boolean value that allows the TextBox control to display text in
more than one line. Each line in a text box is a part of an array of strings. This array is exposed through the
Lines property. The Text property returns the entire text box contents as a single string. TextLength is
the total length of the string that text would return. The MaxLength property will limit the length of the
text to the specified amount.
SelectedText, SelectionLength, and SelectionStart all deal with the currently selected text in the text
box. The selected text is highlighted when the control has focus.
The TextBox control adds a couple of interesting properties. AcceptsReturn is a Boolean value that will
allow the TextBox to capture the Enter key. If the value is set to false, the Enter key clicks the default
button on the form. When AcceptsReturn is set to true, pressing the Enter key creates a new line in the
TextBox. CharacterCasing determines the casing of the text in the text box. The CharacterCasing
enumeration contains three values, Lower, Normal, and Upper. Lower lowercases all text regardless of how
it is entered, Upper renders all text in uppercase letters, and Normal displays the text as it is entered. The
PasswordChar property takes a char that represents what is displayed to the users when they type text
in the text box. This is typically used for entering passwords and PINs. The text property will return the
actual text that was entered; only the display is affected by this property.
The RichTextBox is a text-editing control that can handle special formatting features. As the name
implies, the RichTextBox control uses Rich Text Format (RTF) to handle the special formatting. You can
make formatting changes by using the Selection properties: SelectionFont, SelectionColor, and
SelectionBullet, and paragraph formatting with SelectionIndent, SelectionRightIndent, and
SelectionHangingIndent. All of the Selection properties work in the same way. If a section of text is
highlighted, a change to a Selection property affects the selected text. If no text is selected, the change
takes effect with any text that is inserted to the right of the current insertion point.
The text of the control can be retrieved by using the Text property or the Rtf property. The Text property
returns just the text of the control, whereas the Rtf property returns the formatted text.
The LoadFile method can load text from a file in a couple of different ways. It can use a string that
represents the path and filename or it can use a stream object. You can also specify the RichText
BoxStreamType. The following table lists the values of RichTextBoxStreamType.
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