这个问题并没有按照我想要的方式解决,但我继续给予奖励:ŁukaszW.pl他的时间和精力。
我正在使用gridview控件和linqdatasource,它的工作正常,我添加了searchBySubject的功能,我添加了WhereParameters,而不是绑定我的gridview(参见下面的代码),但不知何故它不返回任何行,我看到我根据我正在搜索的内容来计算行数。
protected void btnSearch_Click(object sender, EventArgs e)
{
this.LinqDataSource1.WhereParameters["Subject"].DefaultValue = this.txtSubject.Text;
this.GridView1.DataBind();
}
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataSourceID="LinqDataSource1"
EmptyDataText="There are no data records to display.">
<Columns>
<asp:BoundField DataField="UserID" HeaderText="UserID" ReadOnly="True"
SortExpression="UserID" />
<asp:BoundField DataField="Username" HeaderText="Username"
SortExpression="Username" />
<asp:BoundField DataField="FirstName" HeaderText="FirstName"
SortExpression="FirstName" />
<asp:BoundField DataField="LastName" HeaderText="LastName"
SortExpression="LastName" />
<asp:BoundField DataField="Email" HeaderText="Email" SortExpression="Email" />
</Columns>
</asp:GridView>
<asp:LinqDataSource ID="LinqDataSource1" runat="server"
ContextTypeName="MyDataContextDataContext"
onselecting="LinqDataSource_Selecting" >
<WhereParameters>
<asp:Parameter Name="Subject" />
</WhereParameters>
</asp:LinqDataSource>
public List<Reporter> GetInquiries()
{
using (MyDataContextDataContext dc = conn.GetContext())
{
var loadAll = (from spName in dc.spReporter()
select spName);
List<Reporter> reporterList = new List<Reporter>();
foreach (var item in loadAll)
{
reporterList.Add(new Reporter(item.Id, item.InqDate, item.Subject));
}
return reporterList;
}
错误:
The query results cannot be enumerated more than once
答案 0 :(得分:1)
假设您在页面中声明了LinqDataSource这样的内容:
<asp:LinqDataSource ID="LinqDataSource1"
runat="server"
ContextTypeName="MyDataContext"
OnSelecting="LinqDataSource1_Selecting">
<WhereParameters>
<asp:ControlParameter Name="Subject"
ControlID="txtSubject"
PropertyName="Text"
Type="String" />
</WhereParameters>
</asp:LinqDataSource>
您的LinqDataSource.Selecting事件处理程序大致应如下所示:
public void LinqDataSource1_Selecting(object sender, LinqDataSourceSelectEventArgs e)
{
var db = new MyDataContext())
var subjectFilter = e.WhereParameters("Subject");
var reporters = from spName in db.spReporter()
where spName.Subject.Contains(subjectFilter)
select new Reporter(spName.Id, spName.InqDate, spName.Subject);
e.Result = reporters;
}
或者您可以将“主题”作为输入参数添加到存储过程和数据库中的过滤。在这种情况下,事件处理程序将如下所示:
public void LinqDataSource1_Selecting(object sender, LinqDataSourceSelectEventArgs e)
{
var db = new MyDataContext())
var subjectFilter = e.WhereParameters("Subject");
var reporters = from spName in db.spReporter(subjectFilter)
select new Reporter(spName.Id, spName.InqDate, spName.Subject);
e.Result = reporters;
}
相关资源:
答案 1 :(得分:0)
关于这个问题,我看不到你的GetInquiries方法和LinqDataSource之间有任何联系。首先,第二个是,即使有连接,如果你返回列表也不会有效,而不是IQueriable对象......
为了更好地理解与LinqDataSource的绑定,请阅读this Scott Gu's article
另外,我想告诉您,您的GetInquiries方法可以简化为以下形式:
public List<Reporter> GetInquiries()
{
using (MyDataContextDataContext dc = conn.GetContext())
{
return (from spName in dc.spReporter()
select new Reporter(spName.Id, spName.InqDate, spName.Subject)).ToList()
}
---- EDITED ----
替代解决方案的示例:
public List<Reporter> GetInquiries(string subject)
{
using (MyDataContextDataContext dc = conn.GetContext())
{
return (from spName in dc.spReporter()
select new Reporter(spName.Id, spName.InqDate, spName.Subject
where spName.Subject == subject)).ToList()
}
}
protected void btnSearch_Click(object sender, EventArgs e)
{
GridView1.DataSource = GetInquiries(txtSubject.Text);
GridView1.DataBind();
}
----------编辑-------------
protected void btnSearch_Click(object sender, EventArgs e)
{
this.LinqDataSource1.WhereParameters["Subject"].DefaultValue = this.txtSubject.Text;
this.GridView1.DataBind();
}
public void LinqDataSource1_Selecting(object sender, LinqDataSourceSelectEventArgs e)
{
ReporterRepository reporterRepo = new ReporterRepository();
e.Result = reporterRepo.GetInquiries();
}
public IQueryable<Reporter> GetInquiries()
{
return from spName in dc.spReporter()
select new Reporter(spName.Id, spName.InqDate, spName.Subject);
}
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataSourceID="LinqDataSource1" EmptyDataText="There are no data records to display.">
<Columns>
<asp:BoundField DataField="UserID" HeaderText="UserID" ReadOnly="True"
SortExpression="UserID" />
<asp:BoundField DataField="Username" HeaderText="Username"
SortExpression="Username" />
<asp:BoundField DataField="FirstName" HeaderText="FirstName"
SortExpression="FirstName" />
<asp:BoundField DataField="LastName" HeaderText="LastName"
SortExpression="LastName" />
<asp:BoundField DataField="Email" HeaderText="Email" SortExpression="Email" />
</Columns>
</asp:GridView>
<asp:LinqDataSource ID="LinqDataSource1" runat="server" ContextTypeName="MyDataContextDataContext" onselecting="LinqDataSource_Selecting">
<WhereParameters>
<asp:Parameter Name="Subject" />
</WhereParameters>
</asp:LinqDataSource>
此致