HtmlInputText.MaxLength Proprietà

Definizione

Ottiene o imposta il numero massimo di caratteri che possono essere inseriti nella casella di testo.

public:
 property int MaxLength { int get(); void set(int value); };
public int MaxLength { get; set; }
member this.MaxLength : int with get, set
Public Property MaxLength As Integer

Valore della proprietà

Numero massimo di caratteri che possono essere inseriti nella casella di testo.

Esempio

Nell'esempio di codice seguente viene illustrato come utilizzare la MaxLength proprietà per specificare il numero massimo di caratteri che è possibile immettere nella casella di testo.

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

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

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

        Answer = Convert.ToInt32(Value1.Value) + 
            Convert.ToInt32(Value2.Value);
        AnswerMessage.InnerHtml = Answer.ToString();

    }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" > 
<head>
    <title> HtmlInputText Example </title>
</head>
<body>
<form id="form1" runat="server">
    <div>

    <h3> HtmlInputText 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">
                 

            </td>
       </tr>
       <tr align="center">
            <td>

               <input id="Value1"
                      type="Text"
                      size="2"
                      maxlength="3"
                      value="1"
                      runat="server"/>

            </td>
            <td>
                + 
            </td>
            <td>

               <input id="Value2"
                      type="Text"
                      size="2"
                      maxlength="3"
                      value="1"
                      runat="server"/>

            </td>
            <td>
                =
            </td>
            <td>
               
               <span 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:CompareValidator
                    ID="Value1MinCompareValidator"
                    ControlToValidate="Value1"
                    Operator="LessThan"
                    Type="Integer"
                    ValueToCompare="100"
                    ErrorMessage="Please enter an integer less than 100.<br />"
                    Display="Dynamic"
                    runat="server"/>

               <asp:CompareValidator
                    ID="Value1MaxCompareValidator"
                    ControlToValidate="Value1"
                    Operator="GreaterThan"
                    Type="Integer"
                    ValueToCompare="0"
                    ErrorMessage="Please enter an integer greater than 0.<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:CompareValidator
                    ID="Value2MinCompareValidator"
                    ControlToValidate="Value2"
                    Operator="LessThan"
                    Type="Integer"
                    ValueToCompare="100"
                    ErrorMessage="Please enter an integer less than 100.<br />"
                    Display="Dynamic"
                    runat="server"/>

               <asp:CompareValidator
                    ID="Value2MaxCompareValidator"
                    ControlToValidate="Value2"
                    Operator="GreaterThan"
                    Type="Integer"
                    ValueToCompare="0"
                    ErrorMessage="Please enter an integer greater than 0.<br />"
                    Display="Dynamic"
                    runat="server"/>

            </td>
            <td>
                 
            </td>
        </tr>
        <tr align="center">
            <td colspan="4">

                <input type="Submit"
                      name="AddButton"
                      value="Add"
                      onserverclick="AddButton_Click"
                      runat="server"/>

                   

                <input type="Reset"
                      name="AddButton"
                      value="Reset"
                      runat="server"/>

            </td>
            <td>
                 
            </td>
        </tr>
    </table>

    </div>
</form>
</body>
</html>
<%@ Page Language="VB" AutoEventWireup="True" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

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

        Dim Answer As Integer

        Answer = Convert.ToInt32(Value1.Value) + Convert.ToInt32(Value2.Value)
        AnswerMessage.InnerHtml = Answer.ToString()

    End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" > 
<head>
    <title> HtmlInputText Example </title>
</head>
<body>
<form id="form1" runat="server">
    <div>

    <h3> HtmlInputText 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">
                 

            </td>
       </tr>
       <tr align="center">
            <td>

               <input id="Value1"
                      type="Text"
                      size="2"
                      maxlength="3"
                      value="1"
                      runat="server"/>

            </td>
            <td>
                + 
            </td>
            <td>

               <input id="Value2"
                      type="Text"
                      size="2"
                      maxlength="3"
                      value="1"
                      runat="server"/>

            </td>
            <td>
                =
            </td>
            <td>
               
               <span 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:CompareValidator
                    ID="Value1MinCompareValidator"
                    ControlToValidate="Value1"
                    Operator="LessThan"
                    Type="Integer"
                    ValueToCompare="100"
                    ErrorMessage="Please enter an integer less than 100.<br />"
                    Display="Dynamic"
                    runat="server"/>

               <asp:CompareValidator
                    ID="Value1MaxCompareValidator"
                    ControlToValidate="Value1"
                    Operator="GreaterThan"
                    Type="Integer"
                    ValueToCompare="0"
                    ErrorMessage="Please enter an integer greater than 0.<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:CompareValidator
                    ID="Value2MinCompareValidator"
                    ControlToValidate="Value2"
                    Operator="LessThan"
                    Type="Integer"
                    ValueToCompare="100"
                    ErrorMessage="Please enter an integer less than 100.<br />"
                    Display="Dynamic"
                    runat="server"/>

               <asp:CompareValidator
                    ID="Value2MaxCompareValidator"
                    ControlToValidate="Value2"
                    Operator="GreaterThan"
                    Type="Integer"
                    ValueToCompare="0"
                    ErrorMessage="Please enter an integer greater than 0.<br />"
                    Display="Dynamic"
                    runat="server"/>

            </td>
            <td>
                 
            </td>
        </tr>
        <tr align="center">
            <td colspan="4">

                <input type="Submit"
                      name="AddButton"
                      value="Add"
                      onserverclick="AddButton_Click"
                      runat="server"/>

                   

                <input type="Reset"
                      name="AddButton"
                      value="Reset"
                      runat="server"/>

            </td>
            <td>
                 
            </td>
        </tr>
    </table>

    </div>
</form>
</body>
</html>

Commenti

Utilizzare la MaxLength proprietà per specificare o determinare il numero massimo di caratteri che è possibile immettere nella casella di testo.

Si applica a

Vedi anche