Skip to content

TextBox

The TextBox component displays a single-line text box, multi-line text area, or specialized HTML5 input control (password, email, number, date, etc.) for user input.

Original Microsoft documentation: https://docs.microsoft.com/en-us/dotnet/api/system.web.ui.webcontrols.textbox?view=netframework-4.8

Features Supported in Blazor

  • Single-line text input (<input type="text">)
  • Multi-line text area (<textarea>)
  • Password input (<input type="password">)
  • HTML5 input types (email, number, date, url, tel, etc.)
  • Two-way data binding with @bind-Text
  • MaxLength validation
  • ReadOnly and Enabled/Disabled states
  • Rows and Columns for sizing
  • Placeholder text
  • All style properties (BackColor, ForeColor, BorderColor, CssClass, Width, Height, etc.)
  • TabIndex support

Web Forms Features NOT Supported

  • AutoPostBack - Not needed in Blazor; use event handlers instead
  • AutoComplete - Handled by browser settings
  • TextChanged server event - Use @bind-Text or @onchange event in Blazor
  • Wrap - Use CSS styling instead

Web Forms Declarative Syntax

<asp:TextBox
    AccessKey="string"
    AutoCompleteType="None|Disabled|Search|FirstName|LastName|MiddleName|
        NamePrefix|NameSuffix|FullName|Nickname|Email|HomePhone|WorkPhone|
        CellPhone|HomeStreetAddress|HomeCity|HomeState|HomeZipCode|
        HomeCountryRegion|WorkStreetAddress|WorkCity|WorkState|WorkZipCode|
        WorkCountryRegion|Gender|Birthday|Occupation|BusinessUrl|
        Company|Department|DisplayName|JobTitle|Notes"
    AutoPostBack="True|False"
    BackColor="color name|#dddddd"
    BorderColor="color name|#dddddd"
    BorderStyle="NotSet|None|Dotted|Dashed|Solid|Double|Groove|Ridge|
        Inset|Outset"
    BorderWidth="size"
    Columns="integer"
    CssClass="string"
    Enabled="True|False"
    Font-Bold="True|False"
    Font-Italic="True|False"
    Font-Names="string"
    Font-Overline="True|False"
    Font-Size="string|Smaller|Larger|XX-Small|X-Small|Small|Medium|
        Large|X-Large|XX-Large"
    Font-Strikeout="True|False"
    Font-Underline="True|False"
    ForeColor="color name|#dddddd"
    Height="size"
    ID="string"
    MaxLength="integer"
    OnTextChanged="TextChanged event handler"
    Placeholder="string"
    ReadOnly="True|False"
    Rows="integer"
    runat="server"
    TabIndex="integer"
    Text="string"
    TextMode="SingleLine|MultiLine|Password|Color|Date|DateTime|
        DateTimeLocal|Email|Month|Number|Range|Search|Phone|Time|Url|Week"
    ToolTip="string"
    Visible="True|False"
    Width="size"
    Wrap="True|False"
/>

Blazor Razor Syntax

Single-Line Text Input

<TextBox Text="Enter your name" CssClass="form-control" />

Two-Way Data Binding

<TextBox @bind-Text="userName" />

@code {
    private string userName = "John Doe";
}

Password Input

<TextBox TextMode="TextBoxMode.Password" Placeholder="Enter password" />

Multi-Line Text Area

<TextBox TextMode="TextBoxMode.MultiLine" 
         Rows="5" 
         Columns="40" 
         @bind-Text="comments" />

HTML5 Input Types

<!-- Email -->
<TextBox TextMode="TextBoxMode.Email" Placeholder="email@example.com" />

<!-- Number -->
<TextBox TextMode="TextBoxMode.Number" />

<!-- Date -->
<TextBox TextMode="TextBoxMode.Date" />

<!-- URL -->
<TextBox TextMode="TextBoxMode.Url" Placeholder="https://example.com" />

<!-- Phone -->
<TextBox TextMode="TextBoxMode.Phone" Placeholder="(555) 123-4567" />

ReadOnly and Disabled

<TextBox Text="Read only text" ReadOnly="true" />
<TextBox Text="Disabled text" Enabled="false" />

With MaxLength Validation

<TextBox MaxLength="10" Placeholder="Max 10 characters" />

Styled TextBox

<TextBox Text="Styled input"
         BackColor="WebColor.LightYellow"
         ForeColor="WebColor.Navy"
         BorderColor="WebColor.Blue"
         BorderWidth="Unit.Pixel(2)"
         BorderStyle="BorderStyle.Solid"
         Width="Unit.Pixel(300)" />

HTML Output

Single-Line TextBox

Web Forms Input: 

<asp:TextBox ID="txtName" Text="John" CssClass="form-control" runat="server" />

Rendered HTML: 

<input type="text" value="John" class="form-control" />

Password TextBox

Web Forms Input: 

<asp:TextBox ID="txtPass" TextMode="Password" runat="server" />

Rendered HTML: 

<input type="password" />

Multi-Line TextBox

Web Forms Input: 

<asp:TextBox ID="txtComments" TextMode="MultiLine" Rows="5" Columns="40" runat="server" />

Rendered HTML: 

<textarea rows="5" cols="40"></textarea>

Migration Notes

When migrating from Web Forms to Blazor:

  1. Remove runat="server" - Not needed in Blazor
  2. Remove AutoPostBack - Use @bind-Text or event handlers
  3. Replace OnTextChanged with @bind-Text - For real-time updates
  4. Update TextMode references - Use TextBoxMode. enum prefix (e.g., TextBoxMode.Password)
  5. Use HTML5 input types - Take advantage of new types like Email, Number, Date, etc.

See Also