控件的设计时支持（ControlDesigner）

最新推荐文章于 2023-02-09 15:03:17 发布

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这是一个关于自定义控件设计时支持的示例，实现了`ControlDesigner`类以提供设计时HTML。`GetPersistInnerHtml`返回控件的状态。`GetDesignTimeHtml`在捕获异常时调用`GetErrorDesignTimeHtml`显示错误信息，`GetEmptyDesignTimeHtml`则在没有内容显示时给出提示。

public class TestDesigner : ControlDesigner
    {


        public override string GetPersistInnerHtml()
        {
                  return text.ToString();
        }

        public override string GetDesignTimeHtml()
        {
            try
            {
                            return “();
             }
            catch (Exception e)
            {
                return GetErrorDesignTimeHtml(e);
            }
        }

        protected override string GetEmptyDesignTimeHtml()
        {
            //Render design time warning if there's nothing to display.
            string text = "Please add Services to the toolbar.";
            return CreatePlaceHolderDesignTimeHtml(text);
        }

        protected override string GetErrorDesignTimeHtml(Exception e)
        {
            string text = string.Format("{0}{1}{2}{3}",
                "There was an error and the control can't be displayed.",
                "<BR>", "Exception: ", e.Message);

return CreatePlaceHolderDesignTimeHtml(text);
}

}

[Designer(typeof(ScriptManagerDesigner))]

public class Test

{

}