GridView，它必须是 IListSource、IEnumerable 或 IDataSource

Question

这是我的源代码

<asp:GridView ID="gveducationInfo" CssClass="footable" runat="server" AutoGenerateColumns="false" Style="max-width: 600px" ShowHeaderWhenEmpty="true" DataKeyNames="Education_ID" OnRowCommand="gveducationInfo_RowCommand">
    <Columns>
        <asp:BoundField DataField="Education_ID" HeaderText="" ItemStyle-CssClass="hiddenColumn" HeaderStyle-CssClass="hiddenColumn" />
        <asp:BoundField DataField="Degree_Type" />
        <asp:BoundField DataField="Name" HeaderText="Name" />
        <asp:BoundField DataField="Year_Of_Passing" HeaderText="Year Of Passing" />
        <asp:BoundField DataField="Institute_Name" HeaderText="Institute Name" />
        <asp:BoundField DataField="State_ID" HeaderText="State" />
        <asp:BoundField DataField="City_ID" HeaderText="City" />
        <asp:BoundField DataField="Name" HeaderText="Name" />
        <%--<asp:BoundField DataField="Notes" HeaderText="Notes" />--%>
        <asp:ButtonField ButtonType="Image" ImageUrl="~/images/edit16.png" CommandName="EditRow" ItemStyle-CssClass="align-center" />
        <asp:ButtonField ButtonType="Image" ImageUrl="~/images/delete16.png" CommandName="DeleteRow" ItemStyle-CssClass="align-center" />
    </Columns>
</asp:GridView>

这是我的 C# 代码

protected void butSave_ServerClick(object sender, EventArgs e)
{
    Business.ATS.ATS ats = new Business.ATS.ATS();
    Data.Education_Info education_Info = new Data.Education_Info();
    var state = ats.GetStates();
    var city = ats.GetCities();
    education_Info = ats.GetEducationInfo(Applicant_ID).SingleOrDefault();
    education_Info = new Data.Education_Info();
    education_Info.Education_ID = 0;
    education_Info.Applicant_ID = Applicant_ID;
    education_Info.Name = txtdegreename.Value;
    education_Info.Year_Of_Passing = txtyearofpassing.Value;
    education_Info.Institute_Name = txtnameofinstitution.Value;
    education_Info.City_ID = Convert.ToInt32(ddlcity.SelectedValue);
    education_Info.State_ID = Convert.ToInt32(ddlstate.SelectedValue);
    education_Info.Degree_Type = Convert.ToInt32(ddldegreetype.SelectedValue);
    ats.SaveEducationalInfo(education_Info);
    gveducationInfo.DataSource = ats.GetEduInfo().Last();
    gveducationInfo.DataBind();
}

这是我的实体框架数据库代码

public IList<Education_Info> GetEduInfo()
{
    using (Data.ATSEntities dc = new Data.ATSEntities())
    {
        var lsteducationinfo = dc.Education_Info.ToList();
        return lsteducationinfo;
    }
}

当我在网页中填写详细信息并单击保存页面时，我需要获取用户在 gridview 中输入的最后一条记录，但出现错误

数据源是无效类型。它必须是 IListSource， IEnumerable 或 IDataSource。

有人知道怎么搭吗？？

Answer 1

对Last()的调用是问题所在：

gveducationInfo.DataSource = ats.GetEduInfo().Last();

像这样删除对Last()的调用：

gveducationInfo.DataSource = ats.GetEduInfo();

为什么？

GetEduInfo 方法返回一个IList，一个IList 实现IEnumerable，它将与DataSource 一起使用。但是，当您调用Last() 时，您不再传递IEnumerable，而是传递了序列的最后一项，这是行不通的。

如果您想将单个项目绑定到您的DataSource，那么您需要将其包装为IEnumerable。您可以使用此Passing a single item as IEnumerable<T> 的任何答案，例如将单个项目包装在数组中：

gveducationInfo.DataSource = new Education_Info[] {ats.GetEduInfo().Last()};