使用EntityDataSource和WHERE过滤数据

Question

嗨,我有一个EntityDataSource.

我需要以编程方式发送变量(@SelectedValue)以在EntityDataSource的WHERE过滤器中使用.

你可以发一个简单的核心来告诉我该怎么做吗？谢谢你的时间!

要在EntityDataSource上创建WhereParameters,我使用以下代码:

            Parameter parameter = new Parameter("SelectedValue", TypeCode.Int32, uxTreeView1.SelectedValue);
            parameter.DefaultValue = "0";
            uxEntityDataSourceNodes.WhereParameters.Add(parameter);`

这里是Control的代码:

        <asp:EntityDataSource ID="uxEntityDataSourceNodes" runat="server" 
        ConnectionString="name=TestHierarchyEntities" 
        DefaultContainerName="TestHierarchyEntities" EnableFlattening="False" 
        EnableUpdate="True" EntitySetName="CmsCategories" Where="it.CategoryId = @SelectedValue" 
        EntityTypeFilter="" Select="">
    </asp:EntityDataSource>

Answer 1

读这个？

The Entity Framework and ASP.NET - Filtering, Ordering, and Grouping Data

更新:Northwind产品和类别表的示例.
DropDownList列出类别,GridView显示按类别筛选的产品.

ASPX

<asp:DropDownList ID="uxTreeView1" runat="server" 
            AutoPostBack="true"
            AppendDataBoundItems="true"
            DataSourceID="EntityDataSource1" 
            DataTextField="CategoryName" 
            DataValueField="CategoryID" 
            OnSelectedIndexChanged="uxTreeView1_SelectedIndexChanged">
    <asp:ListItem Text="Select Category" Value="0"></asp:ListItem>
</asp:DropDownList>
<asp:EntityDataSource ID="EntityDataSource1" runat="server" 
    ConnectionString="name=NorthwindEntities" 
    DefaultContainerName="NorthwindEntities" EnableFlattening="False" 
    EntitySetName="Categories" Select="it.[CategoryID], it.[CategoryName]">
</asp:EntityDataSource>
<asp:GridView ID="GridView1" runat="server" 
            AutoGenerateColumns="False" 
            DataSourceID="EntityDataSource2"
            DataKeyNames="ProductID">
    <Columns>
        <asp:BoundField DataField="ProductName" HeaderText="ProductName" 
            ReadOnly="True" SortExpression="ProductName" />
        <asp:BoundField DataField="CategoryID" HeaderText="CategoryID" 
            ReadOnly="True" SortExpression="CategoryID" />
    </Columns>
</asp:GridView>
<asp:EntityDataSource ID="EntityDataSource2" runat="server" 
    ConnectionString="name=NorthwindEntities" 
    DefaultContainerName="NorthwindEntities" EnableFlattening="False" 
    EntitySetName="Products" 
    Select="it.[ProductID], it.[ProductName], it.[CategoryID]">
</asp:EntityDataSource>

ASPX.CS

protected void uxTreeView1_SelectedIndexChanged(object sender, EventArgs e)
{
    EntityDataSource2.WhereParameters.Clear();
    EntityDataSource2.AutoGenerateWhereClause = true;
    //alternatively
    //EntityDataSource2.Where = "it.[CategoryID] = @CategoryID";
    EntityDataSource2.WhereParameters.Add("CategoryID", TypeCode.Int32, uxTreeView1.SelectedValue);
}

这是你想要的？