C# 动态添加SEO 信息，不和静态页面重复和叠加

/// <summary>
/// 动态设置 SEO 信息
/// </summary>
/// <param name="title">标题</param>
/// <param name="key">关键字</param>
/// <param name="des">描述</param>
public void setMeta(string title, string key, string des)
{
if (!String.IsNullOrEmpty(title))
{
Page.Title += title;
}
if (!String.IsNullOrEmpty(key))
{
Boolean Edited = false;
for (int a_i = 0; a_i <= Page.Header.Controls.Count - 1; a_i++)
{
if (Page.Header.Controls[a_i].GetType() == typeof(HtmlMeta))
{
HtmlMeta SetMeta = (HtmlMeta)Page.Header.Controls[a_i];

if (SetMeta.Name.ToLower () == "keywords")
{
SetMeta.Content = SetMeta.Content.ToString() + " " + key;
Edited = true;
break;
}
}
}
if (!Edited)
{
HtmlMeta NewKeywords = new HtmlMeta();
NewKeywords.Name = "keywords";
NewKeywords.Content = key;
Page.Header.Controls.Add(NewKeywords);
}
}
if (!String.IsNullOrEmpty(des))
{
Boolean Edited = false;
for (int a_i = 0; a_i <= Page.Header.Controls.Count - 1; a_i++)
{
if (Page.Header.Controls[a_i].GetType() == typeof(HtmlMeta))
{
HtmlMeta SetMeta = (HtmlMeta)Page.Header.Controls[a_i];

if (SetMeta.Name.ToLower() == "description")
{
SetMeta.Content = SetMeta.Content.ToString() + " " + des;
Edited = true;
break;
}
}
}
if (!Edited)
{
HtmlMeta NewKeywords = new HtmlMeta();
NewKeywords.Name = "description";
NewKeywords.Content = des;
Page.Header.Controls.Add(NewKeywords);
}
}
}