Question

我有这个程序：

ALTER procedure dbo.scUsuarioCorrecto
    @usrLogin nvarchar(15),
    @usrPassword nvarchar(255)
AS
    select case when exists 
        (select * from Usuario where usrLogin = 
            @usrLogin and usrPassword = @usrPassword
            AND usrHabilitado = 1) 
        then CAST(1 as bit) else CAST(0 as bit) end as correcto;

我无法改变它，所以我必须解决它，我如何从C＃中捕获该位，我已经连接到数据库并且我能够调用某些程序，但我遇到了这个问题

尝试将参数设置为输出：

SqlParameter result = new SqlParameter("correcto", SqlDbType.Int)
{
   Direction = ParameterDirection.Output
};
cmd.Parameters.Add(result);

但我得到了许多参数＆＃34;＆＃34;错误，抱歉，如果我犯了一个愚蠢的错误，我今天开始使用C＃，我也使用了搜索按钮。

Answer 1

问题是，您正在执行存储过程并尝试读取它，就像有Output parameter一样。如果您无法修改存储过程以提供输出参数，请将代码修改为以下内容：

using (var connection = new SqlConnection())
{
    connection.ConnectionString = "Your Connection String";
    using (var command = new SqlCommand())
    {
        command.Connection = connection;
        command.CommandType = CommandType.StoredProcedure;
        command.CommandText = "scUsuarioCorrecto";
        command.Parameters.AddWithValue("@usrLogin", "Your login");
        command.Parameters.AddWithValue("@usrPassword", "Your password");

        connection.Open();
        using (var adapter = new SqlDataAdapter())
        {
            using (var ds = new DataSet())
            {
                adapter.SelectCommand = command;
                adapter.Fill(ds);

                if (ds.Tables.Count > 0 && ds.Tables[0].Rows.Count > 0)
                {
                    var correcto = (bool)ds.Tables[0].Rows[0]["correcto"];
                } else
                {
                    // Something went wrong
                }
            }
        }
    }
}

Answer 2

我想把它放在我对Icemanind的帖子的评论中（但是为了便于阅读而单独发布）。此版本使用ExecuteScalar：

using (var connection = new SqlConnection())
{
    connection.ConnectionString = "Your Connection String";
    using (var command = new SqlCommand())
    {
        command.Connection = connection;
        command.CommandType = CommandType.StoredProcedure;
        command.CommandText = "scUsuarioCorrecto";
        command.Parameters.AddWithValue("@usrLogin", "Your login");
        command.Parameters.AddWithValue("@usrPassword", "Your password");

        connection.Open();
        object obj = command.ExecuteScalar();
        if (obj is bool)
        {
            bool correcto = (bool)obj;                
        }
        else
        {
           // either empty result set, or value in row is NULL.
        }  
    }
}

关于ExecuteScalar的一般说明：

如果SQL请求导致空结果集，则obj将为null（即C＃为null）。如果结果集至少有一行，但第一列的值为NULL（即SQL Server为NULL），则obj将为DBNull.Value。

Answer 3

该过程仅采用两个参数。在这种情况下，由于它正在进行选择，您应该能够从标准SELECT语句中读取它。

Here's a link to get you started.

Answer 4

问题是您需要使用OUTPUT

设置参数

USE AdventureWorks2008R2;
GO
IF OBJECT_ID('Sales.uspGetEmployeeSalesYTD', 'P') IS NOT NULL
    DROP PROCEDURE Sales.uspGetEmployeeSalesYTD;
GO
CREATE PROCEDURE Sales.uspGetEmployeeSalesYTD
@SalesPerson nvarchar(50),
@SalesYTD money OUTPUT
AS  

    SET NOCOUNT ON;
    SELECT @SalesYTD = SalesYTD
    FROM Sales.SalesPerson AS sp
    JOIN HumanResources.vEmployee AS e ON e.BusinessEntityID = sp.BusinessEntityID
    WHERE LastName = @SalesPerson;
RETURN
GO

获取具有特定数据库

4 个答案: