Programming ASP.NET, 3rd Edition

TextBox Control

The TextBox control can be used for both user input and read-only text display. You can configure it to be single line or multiline or to accept passwords. If you set it to multiline, it automatically wraps unless the Wrap property is set to false. The text it contains can exceed the length of the control displayed on the page. The TextBox, DropDownList, Label, and other text-friendly controls implement the ITextControl interface, which is new to Version 2.0 of ASP.NET. This interface has a single property, Text, which is the visual content of the control.

Table 4-2 lists many of the common properties specific to the TextBox control. If any of these attributes are omitted from the control, then the default value will apply.

Table 4-2. Some properties specific to the TextBox control

Name	Type	Get	Set	Values	Description
AutoPostBack	Boolean	✗	✗	true, false	Determines if automatic postback to server will occur if user changes contents of control. If false, postback to server will not occur until the page is posted, either by a button or another control with AutoPostBack set to true. Default is false.
Columns	Int32	✗	✗	0, 1, 2, and so on	Width of the text box in characters. Default is 0, which indicates the property is not set.
MaxLength	Int32	✗	✗	0, 1, 2, and so on	Maximum number of characters allowed. If MaxLength is greater than Columns, then only a portion of the string will display without using the Home, End, ...