textbox的textmode取为multiline时，其maxlength不起作用解决方法

2019-11-17 04:18:18

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来源：转载

供稿：网友

方法一：验证控件验证(经实践可行)

Setting the Maxength of a TextBox when it is in Multiline, You can use RegularExPRessionValidator control as shown below

<asp:TextBox ID="txtConclusion" MaxLength="200" TextMode="MultiLine" Height="100px" Width="400px" runat="server" />
<asp:RegularExpressionValidator ID="txtConclusionValidator1" ControlToValidate="txtConclusion" Text="超过200字" ValidationExpression="^[/s/S]{0,200}$" runat="server" />

方法二：弹出对话框提示
1.html代码

<HTML>
    <HEAD>
        <title>WebForm6</title>
        <meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
        <meta name="CODE_LANGUAGE" Content="C#">
        <meta name="vs_defaultClientScript" content="javaScript">
        <meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
        <script language="Javascript">
            function isOver(sText,len)
            {
                var intlen=sText.value.length;
                if (intlen>len)
                {
                    alert("The content length must Less than or Equal "+len);
                    sText.focus();
                    sText.select();
                }
            }
        </script>
    </HEAD>
    <body MS_POSITIONING="GridLayout">
        <form id="Form1" method="post" runat="server">
            <asp:TextBox id="txtName" style="Z-INDEX: 102; LEFT: 200px; POSITION: absolute; TOP: 104px" runat="server"
                TextMode="MultiLine" Height="112px" Width="271px"></asp:TextBox>
        </form>
    </body>
</HTML>2.cs代码
private void Page_Load(object sender, System.EventArgs e)
        {
            this.txtName.Attributes.Add("onblur","isOver(this,1000);");
        }
方法三：自定义控件