最佳答案
我正在尝试使用实体框架填充 GridView
,但每次我得到以下错误:
”对象‘ COSIS _ DAL. MemberLoan’上的属性访问器‘ LoanProduct’ 抛出以下异常: ObjectContext 实例已被 已被释放,不能再用于需要 联系。”
我的代码是:
public List<MemberLoan> GetAllMembersForLoan(string keyword)
{
using (CosisEntities db = new CosisEntities())
{
IQueryable<MemberLoan> query = db.MemberLoans.OrderByDescending(m => m.LoanDate);
if (!string.IsNullOrEmpty(keyword))
{
keyword = keyword.ToLower();
query = query.Where(m =>
m.LoanProviderCode.Contains(keyword)
|| m.MemNo.Contains(keyword)
|| (!string.IsNullOrEmpty(m.LoanProduct.LoanProductName) && m.LoanProduct.LoanProductName.ToLower().Contains(keyword))
|| m.Membership.MemName.Contains(keyword)
|| m.GeneralMasterInformation.Description.Contains(keyword)
);
}
return query.ToList();
}
}
protected void btnSearch_Click(object sender, ImageClickEventArgs e)
{
string keyword = txtKeyword.Text.ToLower();
LoanController c = new LoanController();
List<COSIS_DAL.MemberLoan> list = new List<COSIS_DAL.MemberLoan>();
list = c.GetAllMembersForLoan(keyword);
if (list.Count <= 0)
{
lblMsg.Text = "No Records Found";
GridView1.DataSourceID = null;
GridView1.DataSource = null;
GridView1.DataBind();
}
else
{
lblMsg.Text = "";
GridView1.DataSourceID = null;
GridView1.DataSource = list;
GridView1.DataBind();
}
}
错误是提到了 Gridview
的 LoanProductName
列。提到: 我使用 C # ,ASP.net,SQL-Server2008作为后端数据库。
我刚接触实体框架。我不明白为什么我会得到这个错误。有人能帮帮我吗?