Writing html extension that accept list of Lambda expressions for accessing Properties

Question

I want to write a html extension that generate HTML table;

public static class HtmlHelpers
{
    public static IHtmlString DisplayPropreties<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, params Expression<Func<TModel, TProperty>>[] expressions)
    {
        // some code here
    }
}

The problem is when I want to call the method from the view:

@Html.DisplayPropreties(model => m.Id, model => m.Property1, model => m.Property2)

Im getting error:

The type argument for method 'HtmlHelpers.DisplayPropreties(HtmlHelper, params Expression>[])' cannot be inferred with current usage. Try specifying the type arguments explicitly

I did not touch c# for some while (3+y), and I don't fully understand what I need to do.

Answer 1

Demo Online

you can use Json.Net 's Jsonconvert Serialize collection obeject then

DeserializeObject collection to DataTable then

call ConvertDataTableToHTML method get HtmlTable from the DataTable object.

public static class HtmlHelpers
{
    public static string ToHtmlTable(this HashSet<dynamic> obj)
    {
        return ToHtmlTableConverter(obj);
    }

    public static string ToHtmlTable(this ICollection obj) {
        return ToHtmlTableConverter(obj);
    }

    public static string ToHtmlTable(this System.Data.DataTable obj)
    {
        return ConvertDataTableToHTML(obj);
    }

    private static string ToHtmlTableConverter( object obj  )  
    {
        var jsonStr = JsonConvert.SerializeObject(obj);
        var data = JsonConvert.DeserializeObject<System.Data.DataTable>(jsonStr);
        var html = ConvertDataTableToHTML(data);
        return html;
    }

    private static string ConvertDataTableToHTML(System.Data.DataTable dt)
    {
        var html = new StringBuilder("<table>");

        //header
        html.Append("<thead><tr>");
        for (int i = 0; i < dt.Columns.Count; i++)
            html.Append("<th>" + dt.Columns[i].ColumnName + "</th>");
        html.Append("</tr></thead>");

        //body
        html.Append("<tbody>");
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            html.Append("<tr>");
            for (int j = 0; j < dt.Columns.Count; j++)
                html.Append("<td>" + dt.Rows[i][j].ToString() + "</td>");
            html.Append( "</tr>");
        }

        html.Append("</tbody>");
        html.Append("</table>");
        return html.ToString();
    }
}

Answer 2

It's exactly what the error says. You need to specify the type arguments as they can't be inferred, eg:

HtmlHelpers.GenerateTable<Foo, Bar>(model => m.Id, model => m.Property1, model => m.Property2);