Change properties of Web page controls in ASPX.CS

In ASPX.CS

System.Web.UI.HtmlControls.HtmlImage IMG  = (System.Web.UI.HtmlControls.HtmlImage)Page.FindControl("IMG1");
    IMG.Attributes.Add("src", "image/TopPic1.gif");

In ASPX

<img src="image/TopPic.gif" border="0" runat="server" width="630" height="79" usemap="#Navigation"
      id="IMG1" name="IMG1">
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原文地址：https://www.cnblogs.com/cy163/p/260675.html