Asp.net动态生成页面控件的办法

在Asp.net开发中，有时需要在页面中动态添加控件。这些控件可以是普通的html标签，也可以是Asp.net独有的服务器端控件。关于动态写入html标签控件，大家都熟悉，这里就不再表述。本文讨论的重点是：如何动态写入服务器端控件，并且在页面PostBack到Server端时，在Server端来获取被动态写入的服务器端控件的各种属性。下面为一个实例：

需求：
1. 用户在UI上输入一个数值(比如：5)，系统动态为用户加载这个数值的Url Address输入域;
2. 用户输入的Url Address内容需要通过Url格式验证;
3. 用户提交输入内容后，系统给出提交的结果

最终效果：




设计过程：

1. Css样式设置： <style type="text/css"> .item { margin:10px; border-bottom:solid 1px #CCC; } .item2 { margin:5px; } .input { width:200px; } </style> 2．前台页面代码： <div> <div class="item"> Please input a number: <asp:TextBox runat="server" CssClass="item" ID="txtTextCount"></asp:TextBox> <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="txtTextCount" ValidationGroup="CreateTextBox" Display="Dynamic" ErrorMessage="Required to input content!"></asp:RequiredFieldValidator> <asp:RegularExpressionValidator ID="RegularExpressionValidator1" ControlToValidate="txtTextCount" ValidationGroup="CreateTextBox" Display="Dynamic" runat="server" ErrorMessage="Only number is valid!" ValidationExpression="^\d+$"></asp:RegularExpressionValidator>   <asp:Button runat="server" ID="btnCreate" Text="Create TextBox List" ValidationGroup="CreateTextBox" onclick="btnCreate_Click" />   <asp:Button runat="server" ID="btnOK" Text="Get TextBox Content" ValidationGroup="ShowListContent" onclick="btnOK_Click" /> </div> <div runat="server" id="divControls" class="item"></div> <div runat="server" id="divMessage"> </div> </div>

2． 前台页面代码 <div> <div class="item"> Please input a number: <asp:TextBox runat="server" CssClass="item" ID="txtTextCount"></asp:TextBox> <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="txtTextCount" ValidationGroup="CreateTextBox" Display="Dynamic" ErrorMessage="Required to input content!"></asp:RequiredFieldValidator> <asp:RegularExpressionValidator ID="RegularExpressionValidator1" ControlToValidate="txtTextCount" ValidationGroup="CreateTextBox" Display="Dynamic" runat="server" ErrorMessage="Only number is valid!" ValidationExpression="^\d+$"></asp:RegularExpressionValidator>   <asp:Button runat="server" ID="btnCreate" Text="Create TextBox List" ValidationGroup="CreateTextBox" onclick="btnCreate_Click" />   <asp:Button runat="server" ID="btnOK" Text="Get TextBox Content" ValidationGroup="ShowListContent" onclick="btnOK_Click" /> </div> <div runat="server" id="divControls" class="item"></div> <div runat="server" id="divMessage"> </div> </div>

说明， 动态创建的TextBox们将装载到divControls中。

3． 后台代码： ///<summary> /// Create textbox list ///</summary> ///<param name="num">textbox list count</param> private void CreateTextBoxList(int num) { HtmlGenericControl div; HtmlGenericControl span; TextBox txt; RegularExpressionValidator rev; for (int i = 0; i < num; i++) { //创建div div = new HtmlGenericControl(); div.TagName = "div"; div.ID = "divTextBox" + i.ToString(); div.Attributes["class"] = "item2"; //创建span span = new HtmlGenericControl(); span.ID = "spanTextBox" + i.ToString(); span.InnerHtml = "Url Address" + (i+1).ToString() + ":"; //创建TextBox txt = new TextBox(); txt.ID = "txt" + i.ToString(); txt.CssClass = "input"; //创建格式验证控件，并且将其关联到对应的TextBox rev = new RegularExpressionValidator(); rev.ID = "rev" + i.ToString(); rev.ControlToValidate = txt.ID; rev.Display = ValidatorDisplay.Dynamic; rev.ValidationGroup = "ShowListContent"; rev.ValidationExpression = @"(http(s)?://)?([\w-]+\.)+[\w-]+(/[\w- ./?%&=]*)?"; rev.ErrorMessage = "Invalid url Address!"; //添加控件到容器 div.Controls.Add(span); div.Controls.Add(txt); div.Controls.Add(rev); divControls.Controls.Add(div); } } protected void Page_Load(object sender, EventArgs e) { if (this.IsPostBack) { int txtCount = int.Parse(txtTextCount.Text); // 注意：每次PostBack时，都需要重新动态创建TextBox CreateTextBoxList(txtCount); } } protected void btnCreate_Click(object sender, EventArgs e) { txtTextCount.Enabled = false; btnCreate.Enabled = false; } protected void btnOK_Click(object sender, EventArgs e) { TextBox txt; StringBuilder sbResult = new StringBuilder() ; int txtCount = int.Parse(txtTextCount.Text); //遍历获取动态创建的TextBox们中的Text值 for (int i = 0; i < txtCount; i++) { //注意：这里必须通过上层容器来获取动态创建的TextBox，才能获取取ViewState内容 txt = divControls.FindControl("txt" + i.ToString()) as TextBox; if (txt != null && txt.Text.Trim().Length > 0) { sbResult.AppendFormat("Url Address{0}: {1}.<br />", i+1, txt.Text.Trim()); } } divMessage.InnerHtml = sbResult.ToString(); }