RadTreeList ChildItems列表为null

Question

我对Telerik的RadTreeList控件有疑问。当我将数据加载到RadTreeList时，只有在单击“展开”按钮时才能访问其子项。如果不进行扩展，ChildItems列表为空。有没有办法让特定父母的孩子不扩展？

Answer 1

子项目仅在展开父项目时出现在控件中。但是，可以在代码中扩展项目以访问子项目。 （如果您不想将其展开，则可以将父级恢复到其折叠状态。）

由于控制生命周期中发生的事情，需要一点小心：

private bool isGetChildItems = false;

protected void Page_Load(object sender, EventArgs e)
{
    if (IsPostBack)
    {
        //if ( your condition that requires access to  child items )
        {
            isGetChildItems = true;
            //your logic to expand whichever nodes you need
            RadTreeList1.Items[0].Expanded = true;
        }
    }
}

protected void RadTreeList1_DataBound(object sender, EventArgs e)
{
    //At this point in the lifecycle we can access the child items
    if (isGetChildItems)
    {
        //Do whatever it is we need to do with the child items
        ScriptManager.RegisterStartupScript(this.Page, this.GetType(), "", string.Format("alert('Item 0 has {0} child items')", RadTreeList1.Items[0].ChildItems.Count), true);
    }
}

protected void RadTreeList1_PreRender(object sender, EventArgs e)
{
    if (isGetChildItems)
    {
        //Restore node state, clear our flag and rebind
        isGetChildItems = false;
        RadTreeList1.Items[0].Expanded = false;
        RadTreeList1.DataBind();
    }
}