[转]ASP.NET MVC HtmlHelper扩展之Calendar日期时间选择

本文转自：http://blog.bossma.cn/asp_net_mvc/asp-net-mvc-htmlhelper-calendar-datetime-select/

 

这里我们扩展HtmlHelper，就像它包含在ASP.NET MVC中一样，扩展方法使我们能为已有的类添加方法。这里使用了一个日期时间选择控件：My97DatePicker，需要添加到网站中，并在页面中引用。

先看看是怎么扩展的：

using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using System.Linq.Expressions;

namespace System.Web.Mvc
{
    /// <summary>
    /// Extended the HtmlHelper for Calendar
    /// </summary>
    public static class CalendarExtensions
    {
        private static string defaultFormat = "yyyy-MM-dd" ;

        /// <summary>
        /// 使用特定的名称生成控件
        /// </summary>
        /// <param name="helper">HtmlHelper对象</param>
        /// <param name="name">控件名称</param>
        /// <returns>Html文本</returns>
        public static string Calendar( this HtmlHelper helper, string name)
        {
            return Calendar(helper, name, defaultFormat);
        }

        /// <summary>
        /// 使用特定的名称生成控件
        /// </summary>
        /// <param name="helper">HtmlHelper对象</param>
        /// <param name="name">控件名称</param>
        /// <param name="format">显示格式</param>
        /// <returns>Html文本</returns>
        public static string Calendar( this HtmlHelper helper, string name, string format)
        {
            return GenerateHtml(name, null , format);
        }

        /// <summary>
        /// 使用特定的名称和初始值生成控件
        /// </summary>
        /// <param name="helper">HtmlHelper对象</param>
        /// <param name="name">控件名称</param>
        /// <param name="date">要显示的日期时间</param>
        /// <returns>Html文本</returns>
        public static string Calendar( this HtmlHelper helper, string name, DateTime date)
        {
            return Calendar(helper, name, date, defaultFormat);
        }

        /// <summary>
        /// 使用特定的名称和初始值生成控件
        /// </summary>
        /// <param name="helper">HtmlHelper对象</param>
        /// <param name="name">控件名称</param>
        /// <param name="date">要显示的日期时间</param>
        /// <param name="format">显示格式</param>
        /// <returns>Html文本</returns>
        public static string Calendar( this HtmlHelper helper, string name, DateTime date, string format)
        {
            return GenerateHtml(name, date, format);
        }

        /// <summary>
        /// 通过lambda表达式生成控件
        /// </summary>
        /// <param name="helper">HtmlHelper对象</param>
        /// <param name="expression">lambda表达式，指定要显示的属性及其所属对象</param>
        /// <returns>Html文本</returns>
        public static string CalendarFor<TModel, TProperty>( this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression)
        {
            return CalendarFor(helper, expression, defaultFormat);
        }

        /// <summary>
        /// 通过lambda表达式生成控件
        /// </summary>
        /// <param name="helper">HtmlHelper对象</param>
        /// <param name="expression">lambda表达式，指定要显示的属性及其所属对象</param>
        /// <param name="format">显示格式</param>
        /// <returns>Html文本</returns>
        public static string CalendarFor<TModel, TProperty>( this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression, string format)
        {
            string name = ExpressionHelper.GetExpressionText(expression);
            DateTime value;

            object data = ModelMetadata.FromLambdaExpression<TModel, TProperty>(expression, helper.ViewData).Model;
            if (data != null && DateTime.TryParse(data.ToString(), out value))
            {
                return GenerateHtml(name, value, format);
            }
            else
            {
                return GenerateHtml(name, null , format);
            }
        }

        /// <summary>
        /// 通过lambda表达式获取要显示的日期时间
        /// </summary>
        /// <param name="helper">HtmlHelper对象</param>
        /// <param name="expression">lambda表达式，指定要显示的属性及其所属对象</param>
        /// <param name="format">显示格式</param>
        /// <returns>Html文本</returns>
        public static string CalendarDisplayFor<TModel, TProperty>( this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression, string format)
        {
            string name = ExpressionHelper.GetExpressionText(expression);
            DateTime value;

            object data = ModelMetadata.FromLambdaExpression<TModel, TProperty>(expression, helper.ViewData).Model;
            if (data != null && DateTime.TryParse(data.ToString(), out value))
            {
                return value.ToString(format);
            }
            else
            {
                return string .Empty;
            }
        }

        /// <summary>
        /// 通过lambda表达式获取要显示的日期时间
        /// </summary>
        /// <param name="helper">HtmlHelper对象</param>
        /// <param name="expression">lambda表达式，指定要显示的属性及其所属对象</param>
        /// <returns>Html文本</returns>
        public static string CalendarDisplayFor<TModel, TProperty>( this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression)
        {
            return CalendarDisplayFor(helper, expression, defaultFormat);
        }

        /// <summary>
        /// 生成输入框的Html
        /// </summary>
        /// <param name="name">calendar的名称</param>
        /// <param name="date">calendar的值</param>
        /// <returns>html文本</returns>
        private static string GenerateHtml( string name, DateTime? date, string format)
        {
            if (date != null )
            {
                return "<input type=\"text\" id=\"" + name + "\" name=\"" + name + "\" onfocus=\"WdatePicker({dateFmt:'" + format + "'})\" class=\"Wdate\" value=\"" + date.Value.ToString(format) + "\" />" ;
            }
            else
            {
                return "<input type=\"text\" id=\"" + name + "\" name=\"" + name + "\" onfocus=\"WdatePicker({dateFmt:'" + format + "'})\" class=\"Wdate\" value=\"\" />" ;
            }
        }
    }
}

使用办法：

日期选择输入框： <%= Html.CalendarFor(model => model.PlanStartTime)%>

显示日期：<%= Html.CalendarDisplayFor(model => model.PlanStartTime)%>

日期时间选择输入框：<%= Html.CalendarFor(model => model.PlanStartTime, “yyyy-MM-dd HH:mm”)%>