c# - 如何从存储过程中获取 SQL 字符串结果并将其保存在 C# Windows 应用程序字符串变量中

Question

我有以下存储过程：

ALTER PROCEDURE [dbo].[ProcedureName] 

    @date NVARCHAR(50)

AS

BEGIN

    SET NOCOUNT ON;

    DECLARE @result nvarchar(500) -- this one should return string.

    DECLARE @variable1 NVARCHAR(50)
    set @variable1 = (SELECT COUNT(*) FROM dbo.Table1 WHERE column1 not in (select column1 from dbo.Table2))

    DECLARE @variable2 NVARCHAR(50)
    update dbo.Table1 set columnX = 1 where column1 not in (select column1 from  dbo.Table2)

    set @variable2 = @@ROWCOUNT

等等......它继续像 200 行脚本一样，至少有 10-12 个变量

之后我想得到这样的结果

'Hello,' + 

'Some Text here' + 

@date +': ' + 

'Explaining text for variable1- ' + @variable1 + 

'Updated rows from variable2 - ' + @variable2 + 

'some other select count - ' + @variable3 +

'some other update rowcount - '+ @variable4

......

到目前为止，我能够使用 PRINT 语句得到它，但不能将它带到我的 C# 代码中的变量，如下所示：

public void Execute_Click(object sender, EventArgs e)
{
    if (MessageBox.Show("Are you sure you want to execute the program?", "Confirm Start", MessageBoxButtons.YesNo, MessageBoxIcon.Question) != DialogResult.No)
    {
        string connectionString = GetConnectionString(usernamePicker.Text, passwordPicker.Text);
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            using (SqlCommand cmd = new SqlCommand("dbo.ProcedureName", connection))
            {
                connection.Open();
                cmd.CommandText = "dbo.ProcedureName";
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.Parameters.Add("@date", SqlDbType.VarChar).Value = dateTimePicker1.Text;

                SqlParameter result = cmd.Parameters.Add("@result", SqlDbType.VarChar);
                result.Direction = ParameterDirection.ReturnValue;

                cmd.ExecuteScalar();
                var resultout = (string)cmd.Parameters["@result"].Value;
                connection.Close();
                TextMessage.Text = dateTimePicker1.Text;
            }
        }
    }
}

我得到的结果是 0 或 NULL 等。我尝试使用 PRINT、RETURN、SET、OUTPUT 从 SQL 返回值......但似乎没有任何效果。然而，从 C# 到 SQL 获取变量似乎是孩子的工作。有任何想法吗？

Answer 1

如果您想将连接字符串作为输出返回，那么在过程结束时只需写入select @result. 确保在此语句之前已将其连接起来。

这将返回您可以在 C# 代码中作为字符串使用的字符串。

Answer 2

将您的存储过程更改为：

ALTER PROCEDURE [dbo].[ProcedureName] 

    @date NVARCHAR(50),
    @variable1 NVARCHAR(50) output,
    @variable2 NVARCHAR(50) output

AS

BEGIN

    SET NOCOUNT ON;

    DECLARE @result nvarchar(500) -- this one should return string.

    set @variable1 = (SELECT COUNT(*) FROM dbo.Table1 WHERE column1 not in (select column1 from dbo.Table2))

    update dbo.Table1 set columnX = 1 where column1 not in (select column1 from  dbo.Table2)

    set @variable2 = @@ROWCOUNT

并像这样修改您的代码：

SqlParameter result1 = cmd.Parameters.Add("@variable1", SqlDbType.VarChar);
result1.Direction = ParameterDirection.ReturnValue;

SqlParameter result2 = cmd.Parameters.Add("@variable2", SqlDbType.VarChar);
result2.Direction = ParameterDirection.ReturnValue;

Answer 3

好的，可以说我做了这个程序

ALTER PROCEDURE [dbo].[ProcedureName] 

    @date NVARCHAR(50),
    @result nvarchar(500) output
AS

BEGIN

    SET NOCOUNT ON;


    DECLARE @variable1 NVARCHAR(50)
    set @variable1 = (SELECT COUNT(*) FROM dbo.Table1 WHERE column1 not in (select column1 from Table2))
    set @result = @variable1 + ' some text '

我希望“@result”从过程中输出文本并使用 C#