asp.net 遍历页面控件包含子控件，变为只读

protected void approval()
{
foreach (Control control in this.Page.Controls)
{
SetReadOnly(control);
}
}

//将单个控件包含子集变为只读
protected void SetReadOnly(Control ctrl)
{
if (!ctrl.HasControls())
{
if (ctrl is TextBox)
{
TextBox tb = (TextBox)ctrl;
tb.Enabled = false;
}
if (ctrl is DropDownList)
{
DropDownList ddl = (DropDownList)ctrl;
ddl.Enabled = false;
}
if (ctrl is FileUpload)
{
FileUpload fu = (FileUpload)ctrl;
fu.Enabled = false;
}

}
else
{
int i = 0;
while (i < ctrl.Controls.Count)
{
SetReadOnly(ctrl.Controls[i]);
i++;
}
}
}