回发后，dropdownlist不显示任何值

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大家好， 我有一个使用webforms的网络应用程序，我在Formview中有两个下拉列表。 我根据选择来填充一个下拉列表其他。只要没有发生回发，我就会看到列表正确填充但在回发后，我的下拉列表是空的。 我正在设置我在运行时填充的ddl的DataValueField属性该ddl的ViewStateMode设置为Enabled。 有谁知道原因是什么？ 非常感谢。

Hi everyone, I have a web application using webforms and I have two dropdown lists inside a Formview. I am populating one dropdownlist based on the selection from the other. As long as there is no postback happening, I see the list getting populated correctly but after a postback, my dropdownlist is empty. I am setting the DataValueField property of the ddl that I populate at runtime and the ViewStateMode for that ddl is set to Enabled. Does anyone know what could be the reason? Thanks much.

推荐答案

我强烈怀疑你在Page_Load事件中绑定了DropDownList。如果是这样，请按如下所示： I strongly suspect you binded your DropDownList in Page_Load event. If so,put it as follows: protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { //bind dropdown here } }

问候......

你指的是基于我填充其他ddl的ddl吗？我在if（！postback）中绑定了那个，但是另一个没有绑定。 我注意到在运行时填充的文本框的内容也会在回发后消失。 我将ddl移到了Formview之外，现在它在回发后保留了它的内容。 Formview中控件的具体内容在运行时填充，我怎么能让它们在回发后保留它们的值？ 谢谢。 Are you referring to the ddl based on which I am populating the other ddl? I do bind that one in if(!postback) but the other one is not bound at all. I noticed that the contents of a text box that is filled at runtime also disappear after postback. I moved the ddl outside of the Formview and now it retains its contents after postback. What is specific about controls inside a Formview that are filled at runtime and how can I make them retain their values after postback? Thanks.