带有多个表过滤的linq查询连接不起作用

Question

我有一个包含四个文本框和两个组合框的表单...

我正在过滤数据并在数据网格视图中显示数据取决于组合框中的选择和文本框中键入的文本..

为此我编写了以下代码

private void btnRunreports_Click(object sender, EventArgs e)
{
    int agefrom = Convert.ToInt32(cbGEFrom.Text);
    int ageto = Convert.ToInt32(cbGETo.Text);
    DateTime today = DateTime.Today;
    DateTime max = today.AddYears(-(agefrom + 1));
    DateTime min = today.AddYears(-(ageto));

    string maximum = Convert.ToString(max);
    string minimum = Convert.ToString(min);

    string gender = "";
    gender = Classes.reportmembers.ConvertGender(cbGEGendertype.Text);
    var mems = Classes.reportmembers
                      .getallreportmembers(gender,
                                           cbGEMembershiptype.SelectedText,
                                           txtlastname.Text,
                                           txtpostcode.Text,
                                           txtcardnum.Text,
                                           txtreference.Text,
                                           cbGEStatustype.SelectedText,
                                           maximum, minimum);
    BindingSource bs = new BindingSource();
    bs.DataSource = mems;
    dgvReportMembers.DataSource = bs;
}

这是我的班级reportmembers：

class ReportMebers
{
    public int MemberID { get; set; }
    public string Lastname { get; set; }
    public string Firstname { get; set; }
    public string Postcode { get; set; }
    public string Reference { get; set; }
    public string CardNum { get; set; }
    public string IsBiometric { get; set; }
    public string DOB { get; set; }
    public string MShipType { get; set; }
    public string StatusType { get; set; }
    public string EndDate { get; set; }
}

 class reportmembers
 {
     public static List<ReportMebers> getallreportmembers(string gender, string membershiptype, string lastname,
                                                    string postcode,string cardnum,string refernce,
                                                      string membershipstatustypesa, string maxage, string minage)
     {

         //CultureInfo provider = CultureInfo.InvariantCulture;
         EclipseEntities eclipse = new EclipseEntities();
        List<ReportMebers> reporall = new List<ReportMebers>();
         var memberreport = from report in eclipse.members
                            join memtomship in eclipse.membertomships on report.member_Id equals memtomship.member_Id
                            join mshoption in eclipse.mshipoptions on memtomship.mshipOption_Id equals mshoption.mshipOption_Id
                            join membershiptypes in eclipse.mshiptypes on mshoption.mshipType_Id equals membershiptypes.mshipType_Id
                            join membershipstatustypes in eclipse.mshipstatustypes on memtomship.mshipStatusType_Id equals membershipstatustypes.mshipStatusType_Id                              
                            where  report.member_Lastname.Equals(lastname)
                            && report.member_CardNum.Equals(cardnum)
                            && report.member_Postcode.Equals(postcode)
                            && report.member_Reference.Equals(refernce)
                            && report.member_Gender.Equals(gender)
                            && membershiptypes.mshipType_Name.Equals(membershiptype)
                            && membershipstatustypes.mshipStatusType_Name.Equals(membershipstatustypesa)
                            && string.Compare(report.member_Dob,maxage) >= 0
                            && string.Compare(report.member_Dob, minage)< 0
                            select new
                            {
                                report.member_Id,
                                report.member_Lastname,
                                report.member_Firstname,
                                report.member_Postcode,
                                report.member_Reference,
                                report.member_CardNum,
                                report.member_IsBiometric,
                                report.member_Dob,
                                membershiptypes.mshipType_Name,
                                membershipstatustypes.mshipStatusType_Name,
                                memtomship.memberToMship_EndDate
                            };
         try
         {
             foreach (var membe in memberreport)
             {

                 ReportMebers allmembersrepor = new ReportMebers();
                 allmembersrepor.MemberID = membe.member_Id;
                 allmembersrepor.Lastname = membe.member_Lastname;
                 allmembersrepor.Firstname = membe.member_Firstname;
                 allmembersrepor.Postcode = membe.member_Postcode;
                 allmembersrepor.Reference = membe.member_Reference;
                 allmembersrepor.CardNum = membe.member_CardNum;
                 allmembersrepor.IsBiometric = membe.member_IsBiometric;
                 allmembersrepor.DOB = membe.member_Dob;
                 allmembersrepor.MShipType = membe.mshipType_Name;
                 allmembersrepor.StatusType = membe.mshipStatusType_Name;
                 allmembersrepor.EndDate = membe.memberToMship_EndDate;
                 reporall.Add(allmembersrepor);

             }
         }
         catch (Exception ex)
         {

             MessageBox.Show(ex.Message);

         }
         return reporall;
     }

如果我在 txtlastname 中输入 robin，则会显示姓氏为 robin 的详细信息...

我已经在数据库中检查了有姓罗宾的人.. 但它不会显示在数据网格视图中...

有没有人帮忙解决这个问题...

非常感谢提前....

Answer 1

您的问题是，您正在对所有字段进行 AND 比较。这意味着，只返回数据库中与所有输入数据匹配的条目！如果您只输入 robin 作为姓氏而不输入其他名称，您将不会得到任何结果，因为所有其他字段都不匹配。更改您的查询以仅包含那些非空字段。像这样的：

var query = from report in eclipse.members
            join memtomship in eclipse.membertomships on report.member_Id equals memtomship.member_Id
            join mshoption in eclipse.mshipoptions on memtomship.mshipOption_Id equals mshoption.mshipOption_Id
            join membershiptypes in eclipse.mshiptypes on mshoption.mshipType_Id equals membershiptypes.mshipType_Id
            join membershipstatustypes in eclipse.mshipstatustypes on memtomship.mshipStatusType_Id equals membershipstatustypes.mshipStatusType_Id;

if(!string.IsNullOrEmpty(lastname))
    query = query.Where(r => r.member_Lastname == lastname);
if(!string.IsNullOrEmptry(cardnum)
    query = query.Where(r => r.member_CardNum == cardnum);
// and so on for all parameters