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TextBox.MaxLength Property

Gets or sets the maximum number of characters allowed in the text box.

[Visual Basic]
Public Overridable Property MaxLength As Integer
[C#]
public virtual int MaxLength {get; set;}
[C++]
public: __property virtual int get_MaxLength();
public: __property virtual void set_MaxLength(int);
[JScript]
public function get MaxLength() : int;
public function set MaxLength(int);

Property Value

The maxumum number of characters allowed in the text box. The default is 0, which indicates that the property is not set.

Exceptions

Exception Type Condition
ArgumentOutOfRangeException The specified width is less than 0.

Remarks

Use the MaxLength property to limit the number of characters that can be entered into the TextBox control.

Note   This property is only applicable when the TextMode property is set to TextBoxMode.SingleLine or TextBoxMode.Password.

Example

[Visual Basic, C#] The following example demonstrates how to use the MaxLength property to limit the number of characters allowed in the TextBox control to 3.

[Visual Basic] 
<%@ Page Language="VB" AutoEventWireup="True" %>

<html> 

<head>

   <script runat="server">

      Protected Sub AddButton_Click(sender As Object, e As EventArgs)

         Dim Answer As Integer

         Answer = Convert.ToInt32(Value1.Text) + Convert.ToInt32(Value2.Text)

         AnswerMessage.Text = Answer.ToString()

      End Sub

   </script>

</head>

<body>

   <form runat="server">

      <h3> TextBox Example </h3>

      <table>

         <tr>

            <td colspan="5">

               Enter integer values into the text boxes. <br>
               Click the Add button to add the two values. <br>
               Click the Reset button to reset the text boxes.

            </td>

         </tr>

         <tr>

            <td colspan="5">

               &nbsp;

            </td>

         </tr>

         <tr align="center">

            <td>

               <asp:TextBox ID="Value1"
                    Columns="2"
                    MaxLength="3"
                    Text="1"
                    runat="server"/>

            </td>

            <td>

               + 

            </td>

            <td>

               <asp:TextBox ID="Value2"
                    Columns="2"
                    MaxLength="3"
                    Text="1"
                    runat="server"/>

            </td>

            <td>

               =

            </td>

            <td>
               
               <asp:Label ID="AnswerMessage"
                    runat="server"/>

            </td>

         </tr>

         <tr>

            <td colspan="2">

               <asp:RequiredFieldValidator
                    ID="Value1RequiredValidator"
                    ControlToValidate="Value1"
                    ErrorMessage="Please enter a value.<br>"
                    Display="Dynamic"
                    runat="server"/>

               <asp:RangeValidator
                    ID="Value1RangeValidator"
                    ControlToValidate="Value1"
                    Type="Integer"
                    MinimumValue="1"
                    MaximumValue="100"
                    ErrorMessage="Please enter an integer <br> between than 1 and 100.<br>"
                    Display="Dynamic"
                    runat="server"/>

            </td>

            <td colspan="2">

               <asp:RequiredFieldValidator
                    ID="Value2RequiredValidator"
                    ControlToValidate="Value2"
                    ErrorMessage="Please enter a value.<br>"
                    Display="Dynamic"
                    runat="server"/>

               <asp:RangeValidator
                    ID="Value2RangeValidator"
                    ControlToValidate="Value2"
                    Type="Integer"
                    MinimumValue="1"
                    MaximumValue="100"
                    ErrorMessage="Please enter an integer <br> between than 1 and 100.<br>"
                    Display="Dynamic"
                    runat="server"/>

            </td>

            <td>

               &nbsp
 
            </td

         </tr>

         <tr align="center">

            <td colspan="4">

               <asp:Button ID="AddButton"
                    Text="Add"
                    OnClick="AddButton_Click"
                    runat="server"/>

            </td>

            <td>

               &nbsp;

            </td>

         </tr>

      </table>

   </form>

</body>
</html>

[C#] 
<%@ Page Language="C#" AutoEventWireup="True" %>

<html> 

<head>

   <script runat="server">

      protected void AddButton_Click(Object sender, EventArgs e)
      {
         int Answer;

         Answer = Convert.ToInt32(Value1.Text) + Convert.ToInt32(Value2.Text);

         AnswerMessage.Text = Answer.ToString();

      }

   </script>

</head>

<body>

   <form runat="server">

      <h3> TextBox Example </h3>

      <table>

         <tr>

            <td colspan="5">

               Enter integer values into the text boxes. <br>
               Click the Add button to add the two values. <br>
               Click the Reset button to reset the text boxes.

            </td>

         </tr>

         <tr>

            <td colspan="5">

               &nbsp;

            </td>

         </tr>

         <tr align="center">

            <td>

               <asp:TextBox ID="Value1"
                    Columns="2"
                    MaxLength="3"
                    Text="1"
                    runat="server"/>

            </td>

            <td>

               + 

            </td>

            <td>

               <asp:TextBox ID="Value2"
                    Columns="2"
                    MaxLength="3"
                    Text="1"
                    runat="server"/>

            </td>

            <td>

               =

            </td>

            <td>
               
               <asp:Label ID="AnswerMessage"
                    runat="server"/>

            </td>

         </tr>

         <tr>

            <td colspan="2">

               <asp:RequiredFieldValidator
                    ID="Value1RequiredValidator"
                    ControlToValidate="Value1"
                    ErrorMessage="Please enter a value.<br>"
                    Display="Dynamic"
                    runat="server"/>

               <asp:RangeValidator
                    ID="Value1RangeValidator"
                    ControlToValidate="Value1"
                    Type="Integer"
                    MinimumValue="1"
                    MaximumValue="100"
                    ErrorMessage="Please enter an integer <br> between than 1 and 100.<br>"
                    Display="Dynamic"
                    runat="server"/>

            </td>

            <td colspan="2">

               <asp:RequiredFieldValidator
                    ID="Value2RequiredValidator"
                    ControlToValidate="Value2"
                    ErrorMessage="Please enter a value.<br>"
                    Display="Dynamic"
                    runat="server"/>

               <asp:RangeValidator
                    ID="Value2RangeValidator"
                    ControlToValidate="Value2"
                    Type="Integer"
                    MinimumValue="1"
                    MaximumValue="100"
                    ErrorMessage="Please enter an integer <br> between than 1 and 100.<br>"
                    Display="Dynamic"
                    runat="server"/>

            </td>

            <td>

               &nbsp
 
            </td

         </tr>

         <tr align="center">

            <td colspan="4">

               <asp:Button ID="AddButton"
                    Text="Add"
                    OnClick="AddButton_Click"
                    runat="server"/>

            </td>

            <td>

               &nbsp;

            </td>

         </tr>

      </table>

   </form>

</body>
</html>

[C++, JScript] No example is available for C++ or JScript. To view a Visual Basic or C# example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 2000, Windows XP Professional, Windows Server 2003 family

See Also

TextBox Class | TextBox Members | System.Web.UI.WebControls Namespace | TextMode

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