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MVC3 razor based htmlhelper with lambda field expressions based on model

I am creating a fluent HtmlHelper in MVC - to create a grid based on HTML. I am aware of mvc contrib and WebGrid - but I am making my own and have a specific problem:

I have to enter this:

@Html.DSGridFor().AddColumn(x=>x.FirstOrDefault().Message)

but I want to be able to type this:

@Html.DSGridFor().AddColumn(x=>x.Message)

The code that gets called when I start with @Html.DSGridFor() - taking in the page based model.

public static DSGridHelper<TModel> DSGridFor<TModel>(this HtmlHelper<TModel> html)
{
   return new DSGridHelper<TModel>(html);
}

and then within the class DSGridHelper I have this:

public DSGridHelper<TModel> AddColumn(Expression<Func<TModel, dynamic>> property, string HeaderText = null)
        {
            string ColumnName = (property.Body as MemberExpression).Member.Name;

            DSGridColumn DSGC = new DSGridColumn();
            DSGC.ColumnName = ColumnName;
            DSGC.HeaderText = HeaderText ?? ColumnName;
            DSColumnList.Add(DSGC);

            return this;
        }

public List<DSGridColumn> DSColumnList { get; set; }

and the column class at the moment is really basic:

  public class DSGridColumn
    {
        public DSGridColumn()
        {

        }

        public string ColumnName { get; set; }
        public string HeaderText { get; set; }

    }

I can get this code working fine with string based column names, but I want the declaring code in the razor page to be simple in format and strongly typed. At the moment I have to type x=>x.First().Message but I really only need x=>x.Message to identify the column.

I appreciate any help.

UPDATE

Thanks to Justin I can now provide my/our code.

View:

@(Html.DSGridFor3().AddColumn(x => x.Message)
                   .AddColumn(x => x.Host)
                   .ToMvcString())

HTML Helper call:

public static DSGridHelper3<T> DSGridFor3<T>(this HtmlHelper<IEnumerable<T>> htmlHelper)
{
         return new DSGridHelper3<T>(htmlHelper);
}

Returning class:

public class DSGridHelper3<T>
    {
        private HtmlHelper _htmlHelper;
        //private IEnumerable<T> _dataList;
        public List<DSGridColumn> DSColumnList { get; set; }

        public DSGridHelper3(HtmlHelper<IEnumerable<T>> htmlHelper)
        {
            _htmlHelper = htmlHelper;
           // _dataList = htmlHelper.ViewData.Model;
            DSColumnList = new List<DSGridColumn>();
        }

        public DSGridHelper3<T> AddColumn(Expression<Func<T, object>> property)
        {
            string columnName = (property.Body as MemberExpression).Member.Name;
            DSGridColumn DSGC = new DSGridColumn();
            DSGC.ColumnName = columnName;
            DSGC.HeaderText = columnName;
            DSColumnList.Add(DSGC);

            return this;
        }

        public MvcHtmlString ToMvcString()
        {
            sb.Append("<table>");
            sb.Append("<tr>");
            sb.Append("<td>");
            sb.Append("hello world within a table");
            sb.Append(@"</td>");
            sb.Append("<td>");
            sb.Append("hello world within a table");
            sb.Append(@"</td>");
            sb.Append(@"</tr>");
            sb.Append(@"</table>");


            return new MvcHtmlString(sb.ToString());

        }
    }

UPDATE 2

If you wanted to manually insert a different type (perhaps because you are going to get a small amount of table data from ViewData rather than the model of the page) then here is some more code:

View:

@(Html.DSGridFor3<DanSoftware.MVC.Areas.Errors.Code.ELMAH_Error>().AddColumn(x => x.Message).ToMvcString();)

Alternative signature for the DSGridHelper ...helper

public static DSGridHelper3<T> DSGridFor3<T>(this HtmlHelper htmlHelper)
        {
            return new DSGridHelp开发者_如何学Pythoner3<T>(htmlHelper);
        }

Additional constructor:

public DSGridHelper3(HtmlHelper htmlHelper)
        {
            _htmlHelper = htmlHelper;
            // _dataList = htmlHelper.ViewData.Model;
            DSColumnList = new List<DSGridColumn>();
        }

Hope this helps someone and thanks Justin!


I dont have Visual Studio with me but I'll take a stab at this...

I would take in a collection as a datatype either in your DsGridFor method or in the AddColumn method. This will allow you to send Strongly-typed arguments from a collection. Say you wanted a generic method of AddColumn for a given collection with access to the class properties vs the collection methods, it would look something like this (just an example):

    public static DSGridHelper<T> AddColumn<T>(this HtmlHelper<IEnumerable<T>> htmlHelper, Expression<Func<T, object>> property) where T : class
    {
        string columnName = (property.Body as MemberExpression).Member.Name;

        DSGridColumn DSGC = new DSGridColumn();
        DSGC.ColumnName = ColumnName;
        DSGC.HeaderText = HeaderText ?? ColumnName;
        DSColumnList.Add(DSGC);

        return this;
    }

For your situation, to new-up a DsGridHelper class I might explicitly set a model-type first and then add overloads as I go:

    public static DSGridHelper<T> DSGridFor<T>(this HtmlHelper<IEnumerable<T>> htmlHelper) where T : class
    {
        return new DSGridHelper<T>(htmlHelper);
    }

And then my DsGridHelper might look something like this:

public class DsGridHelper<T>
{
    private HtmlHelper _htmlHelper;
    private IEnumerable<T> _dataList;

    public DsGridHelper(HtmlHelper<IEnumerable<T>> htmlHelper)
    {
        _htmlHelper = htmlHelper;
        _dataList = htmlHelper.ViewData.Model;
    }

    public DsGridHelper<T> AddColumn(Expression<Func<T, object>> property)
    {
        string columnName = (property.Body as MemberExpression).Member.Name;
        DSGridColumn DSGC = new DSGridColumn();
        DSGC.ColumnName = ColumnName;
        DSGC.HeaderText = HeaderText ?? ColumnName;
        DSColumnList.Add(DSGC);

        return this;
    }
}
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