我想创建一个复合ASP.NET控件,让你建立一个可编辑的控件集合。ASP.NET动态控件计数(创建控件,你去)
我的问题是,当我按下添加或回发按钮(除了要回发表单之外什么都不做),任何输入到文本框中的值都会丢失。
当控件的数量在回发之间发生变化时,我无法使它工作。我需要基本上能够在控制生命周期的两个不同时间重新创建控制树,具体取决于视图状态属性ControlCount
。
该测试可用于重现该问题:
public class AddManyControl : CompositeControl
{
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
EnsureChildControls();
}
protected override void CreateChildControls()
{
var count = ViewState["ControlCount"] as int? ?? 0;
for (int i = 0; i < count; i++)
{
var div = new HtmlGenericControl("div");
var textBox = new TextBox();
textBox.ID = "tb" + i;
div.Controls.Add(textBox);
Controls.Add(div);
}
ViewState["ControlCount"] = count;
var btnAdd = new Button();
btnAdd.ID = "Add";
btnAdd.Text = "Add text box";
btnAdd.Click += new EventHandler(btnAdd_Click);
Controls.Add(btnAdd);
var btnPostBack = new Button();
btnPostBack.ID = "PostBack";
btnPostBack.Text = "Do PostBack";
Controls.Add(btnPostBack);
}
void btnAdd_Click(object sender, EventArgs e)
{
ViewState["ControlCount"] = (int)ViewState["ControlCount"] + 1;
}
protected override void OnPreRender(EventArgs e)
{
base.OnPreRender(e);
// If I remove this RecreateChildControls call
// the collection lags behind each postback
// because the count is incremented in the btnAdd_Click event handler
// however, the values are not lost between postbacks
RecreateChildControls();
}
}
+1为解决方案,它工作正常,我很好奇 – 2011-01-30 13:45:36