从方法返回多个列表 - C＃

Question

确定。所以之前已经提出这个问题，但我无法从这些问题中得到一些提示（可能是因为我对这个通用概念不熟悉）。

所以我的代码是这样的： -

if (dbundle.BoardFK != null && dbundle.ClassesFK != null && dbundle.ClassSubjectFK != null && !string.IsNullOrEmpty(Request.Form["MaterialTypeFK"].ToString()))
{
List<ClassMaterial> ClassMaterialList = null;
ClassMaterialList = PagingList(dbundle);
}
else if (dbundle.DegreeFK != null && dbundle.DegreeStudyFieldFK != null && dbundle.DegreeCourseFK != null && dbundle.DegreeUnivFK != null && dbundle.YearFK != null && dbundle.SemesterFK != null && dbundle.DegreeSubjectFK != null && !string.IsNullOrEmpty(Request.Form["MaterialTypeFK"].ToString()))
{
 dbundle.MaterialIndicator = Convert.ToInt32(Request.Form["MaterialTypeFK"]);
 List<DegreeMaterial> DegreeMaterialList = null;
DegreeMaterialList = PagingList(dbundle);
} // This continues like this

我的PagingList方法返回一个分页列表： -

public AllTblListClass PagingList(DataBundle aListBundle)
    {
        AllTblListClass TblList = new AllTblListClass();

        using (SqlConnection conn = new SqlConnection(Constants.Connection))
        {

            if (!string.IsNullOrEmpty(aListBundle.ListType))
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand("FetchPagedList", conn);
                cmd.CommandType = CommandType.StoredProcedure;

                cmd.Parameters.Add("@ListType", SqlDbType.VarChar, 50).Value = aListBundle.ListType;
                if (aListBundle.ListType.Equals(Constants.ClassSubMatRelation))
                {
                    cmd.Parameters.Add("@BoardFK", SqlDbType.Int).Value = aListBundle.BoardFK;
                    cmd.Parameters.Add("@ClassFK", SqlDbType.Int).Value = aListBundle.ClassesFK;
                    cmd.Parameters.Add("@ClassSubjectFK", SqlDbType.Int).Value = aListBundle.ClassSubjectFK;
                }
                else if (aListBundle.ListType.Equals(Constants.DegreeSubMatRel))
                {
                    cmd.Parameters.Add("@DegreeFK", SqlDbType.Int).Value = aListBundle.DegreeFK;
                    cmd.Parameters.Add("@DegreeStudyFieldFK", SqlDbType.Int).Value = aListBundle.DegreeStudyFieldFK;
                    cmd.Parameters.Add("@DegreeCourseFK", SqlDbType.Int).Value = aListBundle.DegreeCourseFK;
                    cmd.Parameters.Add("@DegreeUnivFK", SqlDbType.Int).Value = aListBundle.DegreeUnivFK;
                    cmd.Parameters.Add("@YearFK", SqlDbType.Int).Value = aListBundle.YearFK;
                    cmd.Parameters.Add("@SemesterFK", SqlDbType.Int).Value = aListBundle.SemesterFK;
                    cmd.Parameters.Add("@DegreeSubjectFK", SqlDbType.Int).Value = aListBundle.DegreeSubjectFK;
                }
                else if (aListBundle.ListType.Equals(Constants.DiplomaSubMatRel))
                {
                    cmd.Parameters.Add("@DiplomaFK", SqlDbType.Int).Value = aListBundle.DiplomaFK;
                    cmd.Parameters.Add("@DiplomaStudyFieldFK", SqlDbType.Int).Value = aListBundle.DiplomaStudyFieldFK;
                    cmd.Parameters.Add("@DiplomaCourseFK", SqlDbType.Int).Value = aListBundle.DiplomaCourseFK;
                    cmd.Parameters.Add("@DiplomaUnivFK", SqlDbType.Int).Value = aListBundle.DiplomaUnivFK;
                    cmd.Parameters.Add("@YearFK", SqlDbType.Int).Value = aListBundle.YearFK;
                    cmd.Parameters.Add("@SemesterFK", SqlDbType.Int).Value = aListBundle.SemesterFK;
                    cmd.Parameters.Add("@DiplomaSubjectFK", SqlDbType.Int).Value = aListBundle.DiplomaSubjectFK;
                }
                else if (aListBundle.ListType.Equals(Constants.CertificateRel))
                {
                    cmd.Parameters.Add("@CertificateFK", SqlDbType.Int).Value = aListBundle.CertificateFK;
                    cmd.Parameters.Add("@CertificateTypeFK", SqlDbType.Int).Value = aListBundle.CertificateTypeFK;
                    cmd.Parameters.Add("@CertSubjectFK", SqlDbType.Int).Value = aListBundle.CertificateSubjectFK;
                }

                cmd.Parameters.Add("@MaterialTypeFK", SqlDbType.Int).Value = aListBundle.MaterialIndicator;

                SqlDataReader reader = null;
                reader = cmd.ExecuteReader();
                if (reader.HasRows)
                    while (reader.Read())
                    {
                        //Want to implement reader here
                    }

                reader.Close();
                cmd.Dispose();
                conn.Close();
            }
        }

        if (aListBundle.ListType.Equals(Constants.ClassSubMatRelation))
        {
            List<ClassMaterial> cm = new List<Models.ClassMaterial>();
            TblList.MatrlObj = cm;
            return TblList.MatrlObj; // want to return list from here
        }

        else
            return null;
    }

我的AllTblListClass类已经添加了所有列表。

public class AllTblListClass
{
    public List<ClassMaterial> MatrlObj { get; set; }
    public List<CourseTbl> Courses { get; set; }
    public List<CourseDesc> CourseDesc { get; set; }
    public List<CourseSubDesc> CourseSubDesc { get; set; }
    public List<Contact> Contacts { get; set; }

}

我的SP FetchPagedList如下： -

Alter Proc FetchPagedList
@PageStart int,
@PageEnd int,
@TblName varchar(200),
@BoardFK int=null, 
@ClassFK int=null, 
@ClassSubjectFK int=null, 
@MaterialTypeFK int=null, 
@ClassMaterialFK int=null,
@DegreeFK int=null, 
@DegreeStudyFieldFK int=null, 
@DegreeCourseFK int=null, 
@DegreeUnivFK int=null, 
@DegreeSubjectFK int=null,
@DiplomaFK int=null, 
@DiplomaStudyFieldFK int=null, 
@DiplomaCourseFK int=null, 
@DiplomaUnivFK int=null, 
@DiplomaSubjectFK int=null,
@YearFK int=null,
@SemesterFK int=null,
@CertificateFK int=null,
@CertificateTypeFK int=null,
@CertSubjectFK int=null
--@YearFK int=null,

作为 开始

SET NOCOUNT ON;
SET XACT_ABORT ON;

BEGIN TRY
BEGIN TRANSACTION;

if(@TblName='ClassSubMatRelation')
BEGIN
    WITH PagingItem AS
    (
        SELECT cm.ClassMaterialID, cm.Name, cm.Description, cm.EbookLink,
        ROW_NUMBER() OVER (ORDER BY ClassSubMatRelationID) AS 'RowNumber'
        FROM ClassSubMatRelation csmr join ClassMaterial cm on cm.ClassMaterialID=csmr.ClassMaterialFK
        where BoardFK = @BoardFK and ClassFK = @ClassFK and ClassSubjectFK=@ClassSubjectFK and MaterialTypeFK=@MaterialTypeFK 
    ) 
    SELECT * FROM PagingItem WHERE RowNumber BETWEEN @PageStart AND @PageEnd;
END

else if(@TblName='DegreeSubMatRel')
BEGIN
    WITH PagingItem AS
    (
        SELECT dm.DegreeMaterialID,
        ROW_NUMBER() OVER (ORDER BY DegreeSubMatRelID) AS 'RowNumber'
        FROM DegreeSubMatRel  dsmr join DegreeMaterial dm on dsmr.DegreeMaterialFK = dm.DegreeMaterialID
        where DegreeFK = @DegreeFK and DegreeStudyFieldFK = @DegreeStudyFieldFK and DegreeCourseFK=@DegreeCourseFK and DegreeUnivFK=@DegreeUnivFK and DegreeSubjectFK=@DegreeSubjectFK and YearFK=@YearFK and SemesterFK=@SemesterFK and MaterialTypeFK=@MaterialTypeFK
    ) 
    SELECT * FROM PagingItem WHERE RowNumber BETWEEN @PageStart AND @PageEnd;
END

else if(@TblName='DiplomaSubMatRel')
BEGIN
    WITH PagingItem AS
    (
        SELECT dm.DiplomaMaterialID, dm.Name, dm.Description,
        ROW_NUMBER() OVER (ORDER BY DiplomaSubMatRelID) AS 'RowNumber'
        FROM DiplomaSubMatRel  dsmr join DiplomaMaterial dm on dsmr.DiplomaMaterialFK = dm.DiplomaMaterialID
        where DiplomaFK = @DiplomaFK and DiplomaStudyFieldFK = @DiplomaStudyFieldFK and DiplomaCourseFK=@DiplomaCourseFK and DiplomaUnivFK=@DiplomaUnivFK and DiplomaSubjectFK=@DiplomaSubjectFK and YearFK=@YearFK and SemesterFK=@SemesterFK and MaterialTypeFK=@MaterialTypeFK
    ) 
    SELECT * FROM PagingItem WHERE RowNumber BETWEEN @PageStart AND @PageEnd;
END

else if(@TblName='CertificateRelRel')
BEGIN
    WITH PagingItem AS
    (
        SELECT cm.CertificateMaterialID, cm.Name, cm.Description, 
        ROW_NUMBER() OVER (ORDER BY CertificateMaterialID) AS 'RowNumber'
        FROM CertificateRel  cr join CertificateMaterial cm on cr.CertificateMaterialFK = cm.CertificateMaterialID
        where CertificateFK = @CertificateFK and CertificateTypeFK = @CertificateTypeFK and CertSubjectFK=@CertSubjectFK and MaterialTypeFK=@MaterialTypeFK
    ) 
    SELECT * FROM PagingItem WHERE RowNumber BETWEEN @PageStart AND @PageEnd;
END

COMMIT TRANSACTION;
END TRY
BEGIN CATCH
    IF (XACT_STATE()) = -1  
    BEGIN  
        ROLLBACK TRANSACTION;  
    END;  

    IF (XACT_STATE()) = 1  
    BEGIN  
        COMMIT TRANSACTION;     
    END;  
END CATCH

结束

我想根据条件值返回列表。但我无法弄清楚如何做到这一点。任何帮助表示赞赏。

Answer 1

关于第二个想法：

而不是返回单个列表 - 为什么不返回容器：

Instead of  --> return TblList.MatrlObj
Do --> return TblList;

在使用PagingList方法时 - 使用相关的内部对象：

ClassMaterialList = PagingList(dbundle).MatrlObj;

你的守则会变得凌乱而且容易出错（下面是我的初步想法）。

由于AllTblListClass和DataBundle是广泛的组合，他们尝试用DB做所有可能的事情，因此编写更清晰的代码有点困难。这是我的尝试：

private void FillClassMaterialsTable(DataBundle dataBundle, ref AllTblListClass dataStore)
{
    // Ado.Net code to call Stored Proc & fetch results
    dataStore.MatrlObj = #List of Data of Relevant Type#
}

private void FillCoursesTable(DataBundle dataBundle, ref AllTblListClass dataStore)
{
    // Ado.Net code to call Stored Proc & fetch results
    dataStore.Courses = #List of Data of Relevant Type#
}

... // So on create simpler 15/20 methods for each Table/Stored Proc call

public AllTblListClass GetDataStore(DataBundle aListBundle)
{
AllTblListClass result = new AllTblListClass();
 switch(aListBundle.ListType)
 {
    case Constants.ClassSubMatRelation:
    {
    FillClassMaterialsTable(aListBundle, ref result);
    }
    break;

    case Constants.ClassCourses:
    {
    FillCoursesTable(aListBundle, ref result);
    }
    break;
 }
 return result;
}

使用个别较小的方法 - 帮助本地化代码更改，不会破坏其他部分。这也有助于测试各个功能。 GetDataStore方法现在更清晰，因为任何新手开发人员都可以遵循代码（简化的switch case）。

理想情况下 - 我会建议所有类型（ClassMaterial，CourseTbl，CourseDesc等）它们都是从常见的东西继承/实现的。这样您就可以使用更简单的返回类型。此外，由于每个表在where子句中都有自己的列 - 重构代码需要花费更多的精力。但我想将ADO.NET代码概括为一个Command Wrapper类 - 您可以在其中传递Table name＆amp; params并从中接收DataTable / DataSet。