Asp.net mvc MVC4输入字段最大长度

我正在显示模型中的占位符，如

@Html.TextBox("",ViewData.TemplateInfo.FormattedModelValue, 
    new { placeholder = ViewData.ModelMetadata.Watermark })

从

Shared\EditorTemplates文件夹，将其命名为String.cshtml

现在，我想从模型中设置maxlength，而不是像下面那样放在我的视图中

在我的模型中

[Required(ErrorMessage = "Please Enter Community Code")]
[Display(Prompt = "Enter Company Code")]
[StringLength(6)]
public string COMPANYCODE { get; set; }

视图：

@Html.EditorFor(model => model.COMPANYCODE, new { @maxlength = "4" })

---

我怎样才能做到这一点

我更改了我的模型和String.cshtml，如下所示

型号：

[Required(ErrorMessage = "Please Enter Community Code")]
[Display(Prompt = "Enter Community Code")]
[AdditionalMetadata("MaxLength", 4)]
public string COMPANYCODE { get; set; }

String.cshtml

@{
    string maxLength = ViewData.ModelMetadata.AdditionalValues.ContainsKey("MaxLength")
        ? ViewData.ModelMetadata.AdditionalValues["MaxLength"].ToString() : null;
}

 @Html.TextBox("", ViewData.TemplateInfo.FormattedModelValue,
       new { placeholder = ViewData.ModelMetadata.Watermark, @class = "form-control", maxlength = maxLength })

视图：

成功了

 @Html.EditorFor(model => model.COMPANYCODE)