Charts Controls 开发系列2

系列目录：  

• 创建Basic Chart -- Completed
• 了解Chart State Management -- Completed
• Chart 外观设置  -- ing
• Chart 数据加载
• 。。。 

了解 Chart State Management

       当我们在使用图表控件开发时，页面经常进行一些postback的操作。如果不了解有关于Chart 的状态管理的方面知识，肯定会遇到问题的。  

比如说：页面postback之后，图表数据丢失问题？。。。  

那如何存储页面上的图表相关数据呢？  

让我们先来了解以下内容  

• SerializationContents
• ChartSerializer
• ViewStateData

 SerializationContents

 主要作用：定义图表序列化的类型

 这个Enum有四种

 1.Appearance
     仅序列化与图表外观有关系的数据内容，如：图表的线的颜色，图表的宽度，高度。。

 2.Data

    仅序列化图表中的Series，不包括与图表外观相关的数据

 3.Default

     仅序列化非默认的图表数据 如：图表数据，图表外表数据
 4.All

    序列化图表中所有的数据

 我们来看看指定不同序列化类型之后生成数据

 

Appearance:

 //仅序列化图表不包括ChartAreas  

<Chart BackColor="211, 223, 240" BackGradientStyle="TopBottom" 
       BackSecondaryColor="White" BorderColor="26, 59, 105" BorderWidth="2">
  <BorderSkin SkinStyle="Emboss" /> 
</Chart> 

 

Data

<Chart>
  <Series>
    <Series Name="Google" XValueType="DateTimeOffset" YValueType="Int32">
      <Points>
        <DataPoint YValues="3" AxisLabel="2010-03-12" />
      </Points>
    </Series>
  </Series>
</Chart> 

 

NonSerializableContent

         语法："Class.Property[,Class.Property]".  

 

    // 设置 有关于图表的BorderColor不进行序列化 
   resultChart.Serializer.NonSerializableContent = *.BorderColor"; 

  

ChartSerializer

主要作用：用于管理用户自定义的View State.

Serializer Data Format一般分四个种 Stream、String、XmlWriter、TextWriter

  

 1.Stream  

   MemoryStream stream = new MemoryStream(); 

   resultChart.Serializer.Save(stream); 

   resultChart.Serializer.Load(stream);

2.String

    resultChart.Serializer.Save("ChartData.xml"); 

    resultChart.Serializer.Load("ChartData.xml");

  

3.XmlWriter

 XmlTextWriter xmlWriter = new XmlTextWriter("c:\\ChartData.xml", Encoding.ASCII);

    resultChart.Serializer.Save(xmlWriter); 

    XmlTextReader xmlReader = new XmlTextReader("c:\\ChartData.xml");

    resultChart.Serializer.Load(xmlReader);

 

4.TextWriter

 private void SetDataToViewStateData () {
            using ( var sw = new StringWriter () ) {
                resultChart.Serializer.Content = SerializationContents.Data;
                resultChart.Serializer.Save ( sw );
                resultChart.ViewStateData = sw.ToString ();
            }
        }

        private void GetDataFromViewStateData () {
            try {
                if ( null != resultChart.ViewStateData ) {
                    using ( var sr = new StringReader ( resultChart.ViewStateData ) ) {
                        resultChart.Serializer.Content = SerializationContents.Data;
                        resultChart.Serializer.Load ( sr );
                    }
                }
            }
            catch ( Exception ) {
                // Data Bind Again
                SetDataToViewStateData ();
            }
        }

   

ViewStateData

     此属性在Framework 3.5中主要是存储序列化数据，而在Framework 4.0中已经Obsolete。  

    MSDN: "ViewStateData has been deprecated. Please investigate Control.ViewState instead."

 

》Framework 3.5

 

  using ( var sw = new StringWriter () ) {
                resultChart.Serializer.Content = SerializationContents.Data;
                resultChart.Serializer.Save ( sw );
                resultChart.ViewStateData = sw.ToString ();
            }

  

》Framework 4.0

Set:          

 using ( var sw = new StringWriter () ) {
                resultChart.Serializer.Content = SerializationContents.All;
                resultChart.Serializer.Save ( sw );
                //resultChart.ViewStateData = sw.ToString ();
               ViewState.Add ( "chartViewState" , sw.ToString () );
            }

 

Get:  

 var query = from vs in ViewState.Keys.OfType<String> ()
            where vs.Contains ( "chartViewState" )
           select ViewState [vs] as String;
 if ( null != query.Single () ) {
      using ( var sr = new StringReader ( query.Single () ) ) {
         resultChart.Serializer.Content = SerializationContents.All;
         resultChart.Serializer.Load ( sr );
      }
}

 

*当然除以上的方式还可以使用其他的方式维护数据状态.

   

提示

      使用State management时，要记得设置EnableViewState属性为true，此属性默认设置为false.

   

嗯，差不多了。