【asp】asp.net MaxLengthValidator 最大长度验证控件代码-net-最大长度验证

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asp.net MaxLengthValidator 最大长度验证控件代码

/// <summary>
/// TextBox的最大长度验证器，如果是varchar，char字段类型，需要此验证
/// </summary>
[Description("对MaxLength进行验证")]
[ToolboxData("<{0}:MaxLengthValidator runat=server></{0}:MaxLengthValidator>")]
public class MaxLengthValidator : BaseValidator
{
/// <summary>
/// 获取或设置是否为非nvarchar,nchar字段验证
/// </summary>
[DefaultValue(true)]
public bool ValidateForNonNationalField
{
get
{
var data=this.ViewState["ValidateForNonNationalField"];
if (data==null)
{
return true;
}
else
{
return (bool)data;
}
}
set
{
this.ViewState["ValidateForNonNationalField"]=value;
}
}

/// <summary>
/// 构造函数
/// </summary>
public MaxLengthValidator()
{
this.ValidateForNonNationalField=true;
}

protected override bool EvaluateIsValid()
{
var targetControlName=this.ControlToValidate;
if (targetControlName==null)
{
//没有目标验证控件，验证通过
return true;
}

var targetControl=this.NamingContainer.FindControl(targetControlName) as TextBox;
if (targetControl==null)
{
//目标控件不是文本框或不存在，验证通过
return true;
}

var maxLength=targetControl.MaxLength;
var targetValue=this.GetControlValidationValue(targetControlName);
var targetLength=0;
if (string.IsNullOrEmpty(targetValue))
{
targetLength=0;
}
else
{
if (this.ValidateForNonNationalField)
{
targetLength=this.GetLengthForNonNationnal(targetValue);
}
else
{
targetLength=targetValue.Length;
}
}

return targetLength <=maxLength;
}

/// <summary>
/// 获得保存为Varchar时，text的长度
/// </summary>
/// <param name="text"></param>
/// <returns></returns>
public virtual int GetLengthForNonNationnal(string text)
{
if (string.IsNullOrEmpty(text))
{
return 0;
}

var length=0;
for (var i=0; i < text.ToCharArray().Length; i++)
{
var charCode=(int)text[i];

length++;
if (charCode > 255)
{
length++;
}
}
return length;
}

protected override void AddAttributesToRender(HtmlTextWriter writer)
{
base.AddAttributesToRender(writer);

if (this.RenderUplevel)
{
writer.AddAttribute("TargetControlID",
this.GetControlRenderID(this.ControlToValidate));
writer.AddAttribute("ValidateForNonNationalField",
this.ValidateForNonNationalField ? "true" : "false");
writer.AddAttribute("evaluationfunction",
"MaxLengthValidator_Validate");

var targetControl=this.NamingContainer.FindControl(this.ControlToValidate) as TextBox;
if (targetControl !=null)
{
var maxLength=targetControl.MaxLength;
writer.AddAttribute("maxlength",
maxLength.ToString());
}
}
}

protected override void OnPreRender(EventArgs e)
{
var script=@"
function MaxLengthValidator_GetNonNationalLength(text) {
if (!text){
return 0;
}
var length=0;
for (var i=0; i < text.length; i++) {
var charCode=text.charCodeAt(i);
length++;
if (charCode > 255) {
length++;
}
}
return length;
}
function MaxLengthValidator_Validate(val) {
if (!val) {
return true;
}
var targetID=val.TargetControlID;
if (!targetID) {
return true;
}
var nonNational=val.ValidateForNonNationalField;
if (!nonNational) {
return true;
}
var target=document.getElementById(targetID);
if (!target) {
return true;
}
var maxLength=val.maxlength;
if (!maxLength || isNaN(maxLength)) {
return true;
}
var targetValue=target.value;
if (!targetValue) {
return true;
}
var realLength=targetValue.length;
if (nonNational=='true')
{
realLength=MaxLengthValidator_GetNonNationalLength(targetValue);
}
return realLength <=parseInt(maxLength);
}";
ScriptManager.RegisterClientScriptBlock(this,
typeof(MaxLengthValidator),
"MaxLengthValidator_Validate",
script,
true);

base.OnPreRender(e);
}
}

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