Razor Substring of Name

Question

I need to get the first initial of the first name

I have the following:

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

I get the following error though when the program tries to run it:

Templates can be used only with field access, property access, single-dimension array index, or single-parameter custom indexer expressions.

Answer 1

Simply add a property to your view model:

public string FirstName { get; set; }

public string FirstLetterOfName
{
    get
    {
        // TODO: a minimum amount of error checking
        // might be good here for cases when FirstName
        // is null or an empty string
        return this.FirstName.Substring(1, 1);
    }
}

and then:

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

---

And if you now tell me that you are not using view models but are directly passing your domain entities to your views (which is very bad design), you might use a custom template:

@Html.DisplayFor(modelItem => item.FirstName, "FirstLetter") 

and then you define a custom display template ~/Views/Shared/DisplayTemplates/FirstLetter.cshtml with the following contents:

@ViewData.TemplateInfo.FormattedModelValue.Substring(1, 1)

Answer 2

You can't do this, because the mapping to your abject wont work like this. Like the exception message tells you you can only use it with properties.

You can however write your own HtmlHelper extension to do what you want

public static class HtmlHelpers
{
    public static MvcHtmlString CustomDisplayFor(this HtmlHelper<Person> htmlHelper, Expression<Func<Person, string>> expression)
    {
          var customBuildString = string.Empty;
          //Make your custom implementation here
          return MvcHtmlString.Create(customBuildString);
    }
}

Answer 3

Before substring, check the length of the string, else you will get index out of range exception;

@MvcHtmlString.Create(item.title.Length > 20 ? @item.title.ToString().Substring(0, 20):@item.title.ToString())