记录ASP.NET页面表单初始状态(主要是为了前台可以根据这个判断页面是否变动了)

浏览数：34 / 时间：2015年06月09日

把页面表单状态记录到HiddenField中.

这里只提供后台代码, 前台逻辑根据需求自由定义.

存放值的ViewState:

protected Dictionary<string, string> HiddenFieldForOriginal
        {
            get
            {
                var data = ViewState["HiddenFieldForOriginal"];
                if (data == null)
                {
                    Dictionary<string, string> ndata = new Dictionary<string, string>();
                    ViewState["HiddenFieldForOriginal"] = ndata;
                }
                return (Dictionary<string, string>)ViewState["HiddenFieldForOriginal"];
            }
        }

记录表单原始值:

        protected void SaveOriginalData(Control control, bool childVisible)
        {
            if (control != null)
            {
                if (control.HasControls()) //有子控件, 往下遍历.
                {
                    foreach (Control item in control.Controls)
                    {
                        if (control.Parent.Visible)                         
                       {
                            SaveOriginalData(item, control.Visible);
                        }
                        else
                        {
                            ////这里逻辑是: 父控件是隐藏的, 子控件也就不记录了.
                            SaveOriginalData(item, control.Parent.Visible);
                        }
                    }
                }
                else
                {
                        string name = control.GetType().Name;

                        string id = control.ClientID + "HiddenField";
                        if (name == "TextBox" || name == "DropDownList" || name == "CheckBox" || name == "RadioButton")
                        {
                            if (childVisible)
                            {
                                if (!HiddenFieldForOriginal.Keys.Contains(id))
                                {
                                    switch (name)
                                    {
                                        case "TextBox": HiddenFieldForOriginal.Add(id, ((TextBox)control).Text); break;
                                        case "DropDownList": HiddenFieldForOriginal.Add(id, ((DropDownList)control).SelectedValue); break;
                                        case "CheckBox": HiddenFieldForOriginal.Add(id, ((CheckBox)control).Checked ? "1" : ""); break;
                                        case "RadioButton": HiddenFieldForOriginal.Add(id, ((RadioButton)control).Checked ? "1" : ""); break;
                                        default: break;
                                    }
                                }
                            }
                            else
                            {

                                if (HiddenFieldForOriginal.Keys.Contains(id))
                                    HiddenFieldForOriginal.Remove(id);
                            }
                        }
                }
            }
        }

以下代码可以放在渲染前事件里面:

Panel defaultPanel = defaultUpdatePanel.FindControl("DefaultPanel") as Panel;
if (defaultPanel != null)
{
      SaveOriginalData(defaultPanel, defaultPanel.Visible);
      foreach (var c in HiddenFieldForOriginal)
      {
            if (!string.IsNullOrEmpty(c.Key))
            {
                  HiddenField hiddenField = null;
                  try
                  {
                        hiddenField = new HiddenField();

                        hiddenField.ID = c.Key;
                        hiddenField.ClientIDMode = System.Web.UI.ClientIDMode.Static;
                        hiddenField.ViewStateMode = System.Web.UI.ViewStateMode.Disabled;
                        hiddenField.Value = c.Value;

                        defaultPanel.Controls.Add(hiddenField);
                   }
                   finally
                   {
                         if (hiddenField != null)
                              hiddenField.Dispose();
                   }
             }
       }
 }