获取 .cshtml 模板中的 MaxLength 值

Question

在我的 class 我有..

public class MyModel
{
    [MaxLength(30)]
    public string Name { get; set; }
}

在我看来..

@Html.AntiForgeryToken()
@Html.EditorForModel()

还有我的String.cshtml

@model string
@{ 
    // How to cetn MaxValue here ??
}

@Html.TextBox(Html.IdForModel().ToString(), Model, new { @class= "text-box single-line", placeholder=ViewData.ModelMetadata.Watermark })

Answer 1

这里是一些基本代码，用于从属性中获取属性。

// use a nullable int to remember (or use a regular int and set a default, whatever your use-case is)
int? maxLength;
PropertyInfo[] props = typeof(MyModel).GetProperties();
foreach (PropertyInfo prop in props)
{
    object[] attrs = prop.GetCustomAttributes(true);
    foreach (object attr in attrs)
    {
        MaxLengthAttribute maxLengthAttr = attr as MaxLengthAttribute;
        if (maxLengthAttr != null &&  prop.Name.Equals("Name"))
        {

            maxLength = maxLengthAttr.Length
        }
    }
}

// check to make sure you got a value. opti
if (maxLength.HasValue)
{
// whatever you want to do
}

Answer 2

您可以使用 AdditionalMetadata 属性代替 StringLength 属性。

[AdditionalMetadata("MaxLength", 30)]
public string Name { get; set; }

您的自定义编辑器模板（String.cshtml）：

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

@Html.TextBox("", Model, new { maxlength = max })

然后你可以使用:

@Html.EditorFor(m => m.Name)

获取 .cshtml 模板中的 MaxLength 值

Get MaxLength value in .cshtml template

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asp.net-mvc-4

razor

mvc-editor-templates