YouTip

## ASP.NET TextBox Text Property The `Text` property is a fundamental property of the ASP.NET Web Server `TextBox` control. It is used to get or set the text content displayed within the text box. --- ## Definition and Usage The `Text` property allows developers to programmatically read the input entered by a user or pre-populate the `TextBox` control with a default string value. This property is commonly used in form submissions, data entry screens, and search bars to capture user input on the server side during a postback. --- ## Syntax ### Declarative Syntax (ASPX Markup) ```aspx ``` ### Property Values | Property Value | Description | | :--- | :--- | | `string` | A string value representing the text content of the `TextBox` control. The default is an empty string (`""`). | --- ## Code Examples ### Example 1: Setting a Default Value in Markup The following example demonstrates how to set an initial default value for a `TextBox` control directly in the ASPX markup. ```aspx

``` ### Example 2: Reading and Writing the Text Property Programmatically In real-world applications, you will often need to read the user's input or update the text dynamically using code-behind (C#). **ASPX Markup (`Default.aspx`):** ```aspx

Name:

``` **Code-Behind (`Default.aspx.cs`):** ```csharp using System; public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { // Set an initial value when the page loads for the first time txtName.Text = "John Doe"; } } protected void btnSubmit_Click(object sender, EventArgs e) { // Read the value entered by the user string userName = txtName.Text; // Display a personalized message lblMessage.Text = "Hello, " + userName + "! Welcome to YouTip."; } } ``` --- ## Key Considerations 1. **AutoPostBack Interaction:** If you set the `AutoPostBack` property of the `TextBox` to `true`, changing the text and moving focus away from the text box will trigger a postback to the server immediately, firing the `TextChanged` event. 2. **HTML Encoding:** By default, ASP.NET performs request validation to prevent Cross-Site Scripting (XSS) attacks. If a user enters HTML tags or scripts into the `TextBox`, ASP.NET will throw a `HttpRequestValidationException` upon submission. 3. **Empty Strings vs. Null:** When a user clears the text box, the `Text` property returns an empty string (`""`), not `null`. It is recommended to use `string.IsNullOrEmpty(txtName.Text)` when validating user input.