MVC Razor need to get Substring

问题:

I have the following inside of my view

     @Html.DisplayFor(modelItem => item.FirstName)

I need to get the first initial of the First Name.

I tried

    @Html.DisplayFor(modelItem => item.FirstName).Substring(1,1) 

but it does not seem to work. I get the following error: .. 'System.Web.Mvc.MvcHtmlString' does not contain a definition for 'Substring' and no extension

回答1:

If you are only wanting to display the first character of item.FirstName why not do:

@Html.DisplayFor(modelItem => item.FirstName.Substring(1,1))

You have it the wrong side of the closing bracket.

回答2:

You could implement in view as follows:

@Html.DisplayFor(modelItem => modelItem.FirstName).ToString().Substring(0,5)

回答3:

You should put a property on your ViewModel for that instead of trying to get it in the view code. The views only responsibility is to display what is given to it by the model, it shouldn't be creating new data from the model.

回答4:

Might I suggest that the view is not the right place to do this. You should probably have a separate model property, FirstInitial, that contains the logic. Your view should simply display this.

  public class Person
  {
       public string FirstName { get; set; }

       public string FirstInitial
       {
           get { return FirstName != null ? FirstName.Substring(0,1) : ""; }
       }

       ...
   }


   @Html.DisplayFor( modelItem => modelItem.FirstInitial )

回答5:

You can use a custom extension method as shown below:

/// <summary>
/// Returns only the first n characters of a String.
/// </summary>
/// <param name="str"></param>
/// <param name="start"></param>
/// <param name="maxLength"></param>
/// <returns></returns>
public static string TruncateString(this string str, int start, int maxLength)
{        
    return str.Substring(start, Math.Min(str.Length, maxLength));
}

Hope this helps...

回答6:

This worked for me (no helper):

@item.Description.ToString().Substring(0, (item.Description.Length > 10) ? 10 : item.Description.Length )