将字符串参数发送到存储过程

Question

我正在处理连接到 SQL 数据库 (MySQL 2008) 的 asp.net C# 项目。这是我的 C# 类：

 public static DataTable GetUnitByName(string unit)
    {
        Database db = DatabaseFactory.CreateDatabase();
        string sqlCommand = "GetUnitByName";
        DbCommand dbCommandWrapper = db.GetStoredProcCommand(sqlCommand);
        db.AddInParameter(dbCommandWrapper, "@Unit", DbType.String, unit);
        DataSet ds = db.ExecuteDataSet(dbCommandWrapper);
        DataTable dt = ds.Tables[0];
        return dt;
    }

这是存储过程：

alter PROCEDURE [dbo].[GetUnitByName]
(
@Unit nvarchar
)
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON
    DECLARE @Err int
    -- Insert statements for procedure here
select * from Unit where Name=@Unit
   SET @Err = @@Error

    RETURN @Err
END

我这样调用程序： DataTable unit1 = Unit.GetUnitByName(per100gText[1]enter code here); , per10gText 是一个字符串列表。 但它返回空数据表。与 sql server 的连接，在调试中我看到该过程无法读取参数。 请提供任何帮助。

Answer 1

如果你想让 proc 返回参数，你需要先将它声明为输出参数

alter PROCEDURE [dbo].[GetUnitByName]
(
@Unit nvarchar , @err int output
)
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON

    -- Insert statements for procedure here
select * from Unit where Name=@Unit
   SET @Err = @@Error

    RETURN @Err
END