How to make entry field to allow numbers only using EF and Data Annotations?

Question

I am trying to figure out if there is a way to make sure that numeric only input is allowed using Data Annotations and Entity Framework.

I am using the following code

[Required]
[DisplayName("Client No")]
[Column("client_no", TypeName = "smallint")]
public virtual Int16 Number { get; set; }

I want this to be displayed using number class.

In one place I use the following

<input type="number" name="searchClientNo" class="numericOnly" /><br />

but in the entry form I am using

@Html.EditorFor(m => m.Number, EditorTemplate.TextBox)

where I have a custom made EditorFor with the following code

<div class="editor-label">
    @Html.Label((ViewData.ModelMetadata.DisplayName??ViewData.ModelMetadata.PropertyName),
        new Dictionary<string, object>
            {
                { "for", ViewData.ModelMetadata.PropertyName }
            })
</div>
<div class="editor-field">
    @Html.TextBox("", (object)Model,
        new Dictionary<string, object>
            {
                { "id", ViewData.ModelMetadata.PropertyName },
                { "name", ViewData.ModelMetadata.PropertyName },
                { "class", "text-box single-line"},
                { "data-bind", "value: " + ViewData.ModelMetadata.PropertyName },
            })
    @Html.ValidationMessage(ViewData.ModelMetadata.PropertyName,
        new Dictionary<string, object>
            {
                { "data-valmsg-for", ViewData.ModelMetadata.PropertyName }
            })
</div>

I am wondering how can I keep this code without changes but still use the numeric only textbox. Do I need to use UIHint?

Or alternatively, is it possible to make my existing EditorFor smarter?

I found this blog post http://robseder.wordpress.com/2012/06/01/uihint-displaytemplates-and-editortemplates-in-mvc/ but I am already using a custom EditorFor. May be I need to add a new type, say, EditorTemplate.NumericTextBox and add another editor? This sounds like it may work, I am going to try this tomorrow...

Thanks a lot in advance.

Answer 1

You could write a custom editor template ~/Views/Shared/EditorTemplates/NumberTemplate.cshtml:

@Html.TextBox("", ViewData.TemplateInfo.FormattedModelValue, new { type = "number" })

and then decorate your view model property with the UIHint attribute:

[Required]
[DisplayName("Client No")]
[Column("client_no", TypeName = "smallint")]
[UIHint("NumberTemplate")]
public virtual Int16 Number { get; set; }

and inside your view:

@Html.EditorFor(x => x.Number)

or if you don't want to use the UIHint attribute on your view model you could define EditorTemplate.NumericTextBox = "NumberTemplate" and then:

@Html.EditorFor(m => m.Number, EditorTemplate.NumericTextBox)

Answer 2

Just want to share my solution in case it may help someone:

My New EditorFor:

<div class="editor-label">
    @Html.Label((ViewData.ModelMetadata.DisplayName??ViewData.ModelMetadata.PropertyName),
        new Dictionary<string, object>
            {                
                { "for", ViewData.ModelMetadata.PropertyName }
            })
</div>

<div class="editor-field">
   @if (ViewData.ModelMetadata.ModelType.IsNumeric())
   {
    @Html.TextBox("", ViewData.TemplateInfo.FormattedModelValue, new { type = "number", @class = "numericOnly"  })      
   }
    else
    {
     @Html.TextBox("", (object)Model,
        new Dictionary<string, object>
            {
                { "id", ViewData.ModelMetadata.PropertyName },
                { "name", ViewData.ModelMetadata.PropertyName },
                { "class", "text-box single-line"},
                { "data-bind", "value: " + ViewData.ModelMetadata.PropertyName },
            })
    }

     @Html.ValidationMessage(ViewData.ModelMetadata.PropertyName,
        new Dictionary<string, object>
            {
                { "data-valmsg-for", ViewData.ModelMetadata.PropertyName }
            })
</div>

And the IsNumeric extension method is based on the code I found in C# MSDN forum and this is its implementation:

/// <summary>
/// Checks is the object is of numeric type 
        /// see http://social.msdn.microsoft.com/Forums/en-US/csharplanguage/thread/66a7dc8d-f276-4d45-8da4-f8d9857db52c/
/// </summary>
/// <param name="obj"></param>
/// <returns></returns>
        public static bool IsNumeric(object obj)
        {
            return (obj == null) ? false : IsNumeric(obj.GetType());
        }

        public static bool IsNumeric(this Type type)
        {
            if (type == null)
                return false;

            TypeCode typeCode = Type.GetTypeCode(type);

            switch (typeCode)
            {
                case TypeCode.Byte:
                case TypeCode.Decimal:
                case TypeCode.Double:
                case TypeCode.Int16:
                case TypeCode.Int32:
                case TypeCode.Int64:
                case TypeCode.SByte:
                case TypeCode.Single:
                case TypeCode.UInt16:
                case TypeCode.UInt32:
                case TypeCode.UInt64:
                    return true;
            }
            return false;
        }