<form id="form1" runat="server"> 
<ul> 
<li id="li1" runat="server">初始值1</li> 
<li id="li2" runat="server">初始值2</li> 
<li id="li3" runat="server">初始值3</li> 
<li id="li4" runat="server">初始值4</li> 
<li id="li5" runat="server">初始值5</li> 
<li id="li6" runat="server">初始值6</li> 
<li id="li7" runat="server">初始值7</li> 
<li id="li8" runat="server">初始值8</li> 
</ul> 
<asp:Button ID="Button1" runat="server" Text="Button" onclick="Button1_Click" /> 
</form>

protected void Button1_Click(object sender, EventArgs e) 
{ 
//单击按钮后批量改变li元素的内联文本值及样式 
for (int i = 1; i <= 8; i++) 
{ 
HtmlGenericControl li = this.FindControl("li" + i) as HtmlGenericControl; 
li.InnerHtml = "新值" + i.ToString(); 
li.Attributes.CssStyle.Value = "color:red"; 
} 
}

<form id="form1" runat="server"> 
<ul id="ul1" runat="server"> 
<li runat="server">初始值1</li> 
<li runat="server">初始值2</li> 
<li runat="server">初始值3</li> 
<li runat="server">初始值4</li> 
<li runat="server">初始值5</li> 
<li runat="server">初始值6</li> 
<li runat="server">初始值7</li> 
<li runat="server">初始值8</li> 
</ul> 
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" /> 
</form>

private int counter = 1; 
protected void Button1_Click(object sender, EventArgs e) 
{ 
//单击按钮后批量改变li元素的内联文本值及样式 
foreach (Control control in ul1.Controls) 
{ 
if (control is HtmlGenericControl) 
{ 
HtmlGenericControl li = control as HtmlGenericControl; 
li.InnerHtml = "新值" + (counter++).ToString(); 
li.Attributes.CssStyle.Value = "color:red"; 
} 
} 
}

<form id="form1" runat="server"> 
<ul id="ul1" runat="server"> 
<li>初始值1</li> 
<li>初始值2</li> 
<li>初始值3</li> 
<li>初始值4</li> 
<li>初始值5</li> 
<li>初始值6</li> 
<li>初始值7</li> 
<li>初始值8</li> 
</ul> 
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" /> 
<asp:Button ID="Button2" runat="server" Text="测试空回发" /> 
</form>

protected void Button1_Click(object sender, EventArgs e) 
{ 
//单击按钮后批量改变li元素的内联文本值及样式 
HtmlDocument htmlDoc = new HtmlDocument(); 
htmlDoc.LoadHtml(ul1.InnerHtml); 
HtmlNodeCollection lis = htmlDoc.DocumentNode.SelectNodes("li"); 
for (int i = 0; i < lis.Count; i++) 
{ 
lis[i].InnerHtml = "新值" + (i + 1).ToString(); 
lis[i].Attributes.Add("style", "color:red"); 
} 
ul1.InnerHtml = htmlDoc.DocumentNode.InnerHtml; 
}