ASPxGridView-如何在客户端缓存数据

　　有时候我们可以直接从后台生成一些值缓存到客户端，在用到的时候无需在进行callback进行取值，减少和服务器的交互。下面的例子缓存列"title_id"和"title"的值。

<dxwgv:aspxgridview id="grid" runat="server" width="950px" AutoGenerateColumns="False"
        DataSourceID="AccessDataSource1" KeyFieldName="title_id"
        OnCustomJSProperties="grid_CustomJSProperties">
    <SettingsPager PageSize="5" />
    <Columns>
        <dxwgv:GridViewDataTextColumn Caption="title_id" FieldName="title_id" ReadOnly="True"
            VisibleIndex="1">
        </dxwgv:GridViewDataTextColumn>
        <dxwgv:GridViewDataTextColumn Caption="title" FieldName="title" VisibleIndex="2">
        </dxwgv:GridViewDataTextColumn>
        <dxwgv:GridViewDataTextColumn Caption="type" FieldName="type" VisibleIndex="3">
        </dxwgv:GridViewDataTextColumn>
        <dxwgv:GridViewDataDateColumn Caption="pubdate" FieldName="pubdate" VisibleIndex="4">
        </dxwgv:GridViewDataDateColumn>
        <dxwgv:GridViewDataTextColumn Caption="price" FieldName="price" VisibleIndex="5">
        </dxwgv:GridViewDataTextColumn>
        <dxwgv:GridViewDataTextColumn Caption="button" VisibleIndex="6">
            <DataItemTemplate>
                <input type="button" value="Click Me" onclick="ProcessRow(<%# Container.VisibleIndex %>);" />
            </DataItemTemplate>
        </dxwgv:GridViewDataTextColumn>
    </Columns>
</dxwgv:aspxgridview>

<script type="text/javascript">

//读取缓存的值
function ProcessRow(index) {
    alert("The row id is '" + grid.cpTitleId[index - grid.visibleStartIndex] + "', and title is " + grid.cpTitles[index - grid.visibleStartIndex]);
}
</script>

//后台缓存代码

protected void grid_CustomJSProperties(object sender, ASPxGridViewClientJSPropertiesEventArgs e)
{
 int startIndex = grid.PageIndex * grid.SettingsPager.PageSize;
 int end = Math.Min(grid.VisibleRowCount, startIndex + grid.SettingsPager.PageSize);
 object[] titleId = new object[end - startIndex], titles = new object[end - startIndex];
 for (int n = startIndex; n < end; n++)
 {
  titleId[n - startIndex] = grid.GetRowValues(n, "title_id");
  titles[n - startIndex] = grid.GetRowValues(n, "title");
 }
 e.Properties["cpTitleId"] = titleId;
 e.Properties["cpTitles"] = titles;
}