"System.Windows.Forms.HtmlDocument" message appears when navigate webbrowser

when I try to set a specific html data stored in string into webbrowser, this message appears instead of html content

System.Windows.Forms.HtmlDocument

my code is : note that html code stored in temp_data

this.main_webpage.Navigate("about:blank");
HtmlDocument d_c = main_webpage.Document;
d_c.Write(temp_data);

main_webpage.DocumentText = d_开发者_如何学Cc.ToString();
main_webpage.Refresh();

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The ToString is the one inherited from Object, which returns the type of the object. HtmlDocument doesn't override it.

Use the Body property of HtmlDocument - it returns the body element:

main_webpage.DocumentText = d_c.Body.InnerHtml;