问ASPMVC4创建类似于Html.BeginForm的自定义html帮助方法

EN

public static class BeginViewHelper
{
    public static IDisposable BeginView(this HtmlHelper helper, string viewId)
    {
        helper.ViewContext.Writer.Write(string.Format("<div id='{0}'>", viewId));

        return new MyView(helper);
    }

    class MyView : IDisposable
    {
        private HtmlHelper helper;

        public MyView(HtmlHelper helper)
        {
            this.helper = helper;
        }

        public void Dispose()
        {
            this.helper.ViewContext.Writer.Write("</div>");
        }
    }
}

TagBuilder tb = new TagBuilder("div");
helper.ViewContext.Writer.Write(tb.ToString(TagRenderMode.StartTag));

@using (Html.BeginWidget("Widget Title", 3 /* columnWidth */))
{
    @* Widget Contents *@
}

/// <summary>
/// Widget container
/// </summary>
/// <remarks>
/// We make it IDIsposable so we can use it like Html.BeginForm and when the @using(){} block has ended,
/// the end of the widget's content is output.
/// </remarks>
public class HtmlWidget : IDisposable
{
    #region CTor

    // store some references for ease of use
    private readonly ViewContext viewContext;
    private readonly System.IO.TextWriter textWriter;

    /// <summary>
    /// Initialize the box by passing it the view context (so we can
    /// reference the stream writer) Then call the BeginWidget method
    /// to begin the output of the widget
    /// </summary>
    /// <param name="viewContext">Reference to the viewcontext</param>
    /// <param name="title">Title of the widget</param>
    /// <param name="columnWidth">Width of the widget (column layout)</param>
    public HtmlWidget(ViewContext viewContext, String title, Int32 columnWidth = 6)
    {
        if (viewContext == null)
            throw new ArgumentNullException("viewContext");
        if (String.IsNullOrWhiteSpace(title))
            throw new ArgumentNullException("title");
        if (columnWidth < 1 || columnWidth > 12)
            throw new ArgumentOutOfRangeException("columnWidth", "Value must be from 1-12");

        this.viewContext = viewContext;
        this.textWriter = this.viewContext.Writer;

        this.BeginWidget(title, columnWidth);
    }

    #endregion

    #region Widget rendering

    /// <summary>
    /// Outputs the opening HTML for the widget
    /// </summary>
    /// <param name="title">Title of the widget</param>
    /// <param name="columnWidth">Widget width (columns layout)</param>
    protected virtual void BeginWidget(String title, Int32 columnWidth)
    {
        title = HttpUtility.HtmlDecode(title);

        var html = new System.Text.StringBuilder();

        html.AppendFormat("<div class=\"box grid_{0}\">", columnWidth).AppendLine();
        html.AppendFormat("<div class=\"box-head\">{0}</div>", title).AppendLine();
        html.Append("<div class=\"box-content\">").AppendLine();

        this.textWriter.WriteLine(html.ToString());
    }

    /// <summary>
    /// Outputs the closing HTML for the widget
    /// </summary>
    protected virtual void EndWidget()
    {
        this.textWriter.WriteLine("</div></div>");
    }

    #endregion

    #region IDisposable

    private Boolean isDisposed;

    public void Dispose()
    {
        this.Dispose(true);
        GC.SuppressFinalize(this);
    }

    public virtual void Dispose(Boolean disposing)
    {
        if (!this.isDisposed)
        {
            this.isDisposed = true;
            this.EndWidget();
            this.textWriter.Flush();
        }
    }

    #endregion
}

public static HtmlWidget BeginWidget(this HtmlHelper htmlHelper, String title, Int32 columnWidth = 12)
{
  return new HtmlWidget(htmlHelper.ViewContext, title, columnWidth);
}