.NET 2.0 TextBox ReadOnly attribute

在.NET 2.0裡面,asp:TextBox的ReadOnly屬性如果被設成true的話(例如: <asp:textbox id="tbx_test" runat="server" />,或是使用tbx_test.ReadOnly = true;),會對前端的javascript造成一點影響,譬如我們常常在前端使用javascrip將textbox的值改變,但是當程式postback到後方以後,會發現textbox所保有的值仍然是舊的值,要想改正這個行為,有幾種方法:

1. 在後端以Request["tbx_test"],或是Request.Form["tbx_test"]來取得改正過後的值,然後用tbx_test.Text = Request["tbx_test"].ToString();在後重新設定textbox的值,

2. 不使用ReadOnly="true"或是tbx_test.ReadOnly = true;,而是在後端使用
tbx_test.Attributes.Add("ReadOnly", "ReadOnly");,或是
tbx_test.Attributes["ReadOnly"] = "ReadOnly";


The Text value of a TextBox control with the ReadOnly property set to true is sent to the server when a postback occurs, but the server does no processing for a read-only text box. This prevents a malicious user from changing a Text value that is read-only. The value of the Text property is preserved in the view state between postbacks unless modified by server-side code. (Quoted from MSDN)

reference: http://darkthread.blogspot.com/2006/11/kb-aspnet-20-textboxreadonly.html