ASP.NET显示渐变图片实现方法

Dictionary<int, int> Datas 
 { 
 get 
 { 
 Dictionary<int, int> d = new Dictionary<int, int>(); 
 d.Add(1, 35); 
 d.Add(2, 45); 
 d.Add(3, 20); 
 return d; 
 } 
 } 

<asp:Label ID="Label1" runat="server" style="margin: 3px;" Text="" Width="300" BorderWidth="1"></asp:Label><br /> 
 <asp:Label ID="Label2" runat="server" style="margin: 3px;" Text="" Width="300" BorderWidth="1"></asp:Label><br /> 
 <asp:Label ID="Label3" runat="server" style="margin: 3px;" Text="" Width="300" BorderWidth="1"></asp:Label><br /> 

protected void Page_Load(object sender, EventArgs e) 
 { 
 Data_Binding(); 
 } 
 
 private void Data_Binding() 
 { 
 int totals = 100; 
 foreach (KeyValuePair<int, int> kvp in Datas) 
 { 
 double rate = kvp.Value / (double)totals; 
 
 double width = rate  300; 
 switch (kvp.Key) 
 { 
 case 1: 
  this.Label1.Text = GradientImage(width, rate); 
  break; 
 case 2: 
  this.Label2.Text = GradientImage(width, rate); 
  break; 
 case 3: 
  this.Label3.Text = GradientImage(width, rate); 
  break; 
 } 
 } 
 } 
 
 private string GradientImage(double width, double rate) 
 { 
 return "<IMG height='21' src='images/bar.gif' width='" + width + "' align='absMiddle'> " + rate.ToString("p"); 
 }