使用实体框架 6 和 C# 调用现有的存储过程

Question

我需要知道如何使用c#在实体框架 6 Code First 中调用现有的存储过程。

以下是我正在使用的程序：

CREATE PROCEDURE proc_getEmployees 
    @departmentname varchar(50),
    @sortCol varchar(30),
    @sortdir varchar(25),
    @searchString varchar(50)
AS
BEGIN
    SET NOCOUNT ON;
    declare @strSQl varchar(1000);
    declare @strSQlwhere varchar(500);
    declare @strSelectEndPart varchar(100);
    
    set @strSQl = ';WITH employeetable as 
                (
                    select ROW_NUMBER() OVER (ORDER BY '+@sortCol+' '+@sortdir+' ) AS RowNumber,COUNT(*) over() as TotalRecords, ID,FirstName,LastName,Designation,DepartmentName,Contact,EmailAddress,Location from Employees ';
    set @strSQlwhere = 'where DepartmentName = '''+@departmentname+'''';
    set @strSQlwhere = @strSQlwhere+ ' and (Id like ''%' + @searchString + '%'' Or FirstName like ''%' + @searchString + '%'' Or LastName like ''%' + @searchString + '%'' Or Designation like ''%' + @searchString + '%'' Or DepartmentName like ''%' + @searchString + '%'' Or Contact like ''%' + @searchString + '%'' Or EmailAddress like ''%' + @searchString + '%'' Or Location like ''%' + @searchString + '%'')';
    set @strSelectEndPart =') select * from employeetable';
                    
    set @strSQl = @strSQl +@strSQlwhere+@strSelectEndPart;
    execute (@strSQl);
END
GO

我正在查询的表是具有以下结构的员工：

Column          Type    Length
ID              int       4
FirstName       varchar   50
LastName        varchar   50
Designation     varchar   50
DepartmentName  varchar   50
Contact         varchar   50
EmailAddress    varchar   50
Location        varchar   50

DBContext 类如下：

public class DevelopmentTestDatabaseContext :DbContext
{
    public DevelopmentTestDatabaseContext() : base("name =DevelopmentTestDatabaseContext")
    {

    }
    public virtual DbSet<Employee> EmployeeData { get; set; }
    
}

调用存储过程的方法如下：

public void GetEmployeeDataUsingProcedure()
{
    object[] parameters = new SqlParameter[4];
    List<EmployeeResultSet> lstEmployees = new List<EmployeeResultSet>();
    try
    {
        using (var db = new DevelopmentTestDatabaseContext())
        {
            SqlParameter param = new SqlParameter("@departmentname", "IT");
            parameters[0] = param;
            param = new SqlParameter("@sortCol", "ID");
            parameters[1] = param;
            param = new SqlParameter("@sortdir", "asc");
            parameters[2] = param;
            param = new SqlParameter("@searchString", "ope");
            parameters[3] = param;

            var results = db.Database.SqlQuery<EmployeeResultSet>("proc_getEmployees @departmentname, @sortCol, @sortdir, @searchString", parameters);
            db.Database.Log = query => System.Diagnostics.Debug.Write(query);
            lstEmployees = results.ToList();
        }
    }
    catch (Exception ex)
    {

    }
}

定义存储过程结果集的类如下：

public class EmployeeResultSet
{
    public int rowNumber { get; set; }
    public int totalRecords { get; set; }
    public int ID { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Designation { get; set; }
    public string DepartmentName { get; set; }
    public string Contact { get; set; }
    public string EmailAddress { get; set; }
    public string Location { get; set; }
}

请让我知道在调用存储过程之前是否需要做任何其他事情。 我是 EF6 的新手并且遇到了问题。 代码中缺少什么？ 我需要在任何课程中进行一些更改吗？

Answer 1

我可以告诉一个问题的一件事是在您调用过程的方法中。 您将数组的所有元素设置为等于param但您一直在更改param 。 您的所有元素都将等于param的最终状态。 试试这个：

public void GetEmployeeDataUsingProcedure()
{
    object[] parameters = new SqlParameter[4];
    List<EmployeeResultSet> lstEmployees = new List<EmployeeResultSet>();
    try
    {
        using (var db = new DevelopmentTestDatabaseContext())
        {
            parameters[0] = new SqlParameter("@departmentname", "IT");
            parameters[1] = new SqlParameter("@sortCol", "ID");
            parameters[2] = new SqlParameter("@sortdir", "asc");
            parameters[3] = new SqlParameter("@searchString", "ope");

            var results = db.Database.SqlQuery<EmployeeResultSet>("proc_getEmployees @departmentname, @sortCol, @sortdir, @searchString", parameters);
            db.Database.Log = query => System.Diagnostics.Debug.Write(query);
            lstEmployees = results.ToList();
        }
    }
    catch (Exception ex)
    {
        //log it or something
    }
}

可能还有其他问题，但无需过多研究，我需要有关您遇到的特定错误或行为的更多信息。

您也可以尝试输入数据库的全名：

"MyDatabase.MySchema.proc_getEmployees @departmentname, @sortCol, @sortdir, @searchString"

编辑根据您的意见：

快速闪避，我发现了这个。 从本质上讲，它指出，如果您在查询中将数字转换为int ，则应该没问题。 所以而不是：

select * from employeetable

尝试：

select CAST(RowNumber as int) as RowNumber, 
    CAST(TotalRecords as int) as TotalRecords, 
    CAST(ID as int) as ID, 
    FirstName, 
    LastName, 
    Designation, 
    DepartmentName, 
    Contact, 
    EmailAddress, 
    Location 
from employeetable

Answer 2

顺便说一句，但您并不是真的有必要使用动态 SQL。 特别是当搜索条件是字符串时，坚持使用参数化查询会更安全。 在您的情况下，您可以执行以下操作：

;WITH employeetable as 
(
    select 
    CASE WHEN @sortDir = 'asc' THEN
    ROW_NUMBER() OVER (ORDER BY 
    CASE WHEN @sortCol = 'ID' THEN ID END,
    CASE WHEN @sortCol = 'FirstName' THEN FirstName END,
    CASE WHEN @sortCol = 'LastName' THEN LastName END,
    CASE WHEN @sortCol = 'Designation' THEN Designation END,
    CASE WHEN @sortCol = 'DepartmentName' THEN DepartmentName END,
    CASE WHEN @sortCol = 'Contact' THEN Contact END,
    CASE WHEN @sortCol = 'EmailAddress' THEN EmailAddress END,
    CASE WHEN @sortCol = 'Location' THEN Location END
    ASC) ELSE ROW_NUMBER() OVER (ORDER BY  
    CASE WHEN @sortCol = 'ID' THEN ID END,
    CASE WHEN @sortCol = 'FirstName' THEN FirstName END,
    CASE WHEN @sortCol = 'LastName' THEN LastName END,
    CASE WHEN @sortCol = 'Designation' THEN Designation END,
    CASE WHEN @sortCol = 'DepartmentName' THEN DepartmentName END,
    CASE WHEN @sortCol = 'Contact' THEN Contact END,
    CASE WHEN @sortCol = 'EmailAddress' THEN EmailAddress END,
    CASE WHEN @sortCol = 'Location' THEN Location END
    DESC) END AS RowNumber,
    COUNT(*) over() as TotalRecords, ID,FirstName,LastName,Designation,
    DepartmentName,Contact,EmailAddress,Location from Employees
    where DepartmentName = @departmentname and 
    (Id like '%' + @searchString + '%' Or FirstName like '%' 
    + @searchString + '%' Or LastName like '%' + @searchString + '%' 
    Or Designation like '%' + @searchString + '%' Or 
    DepartmentName like '%' + @searchString + '%' Or 
    Contact like '%' + @searchString + '%' Or 
    EmailAddress like '%' + @searchString + '%' Or 
    Location like '%' + @searchString + '%')
)
select * from employeetable