C#调用SQL中的存储过程中有output参数，类型是字符型的时候一定要指定参数的长度。不然获取到的结果总是只有第一字符。本人就是由于这个原因，折腾了很久。在此记录一下，供大家以后参考！
例如：
CREATE PROCEDURE sp_AccountRole_Create @CategoryID int, @RoleName nvarchar(10), @Description nvarchar(50), @RoleID int output AS DECLARE @Count int -- 查找是否有相同名称的记录 SELECT @Count = Count(RoleID) FROM Account_Role WHERE RoleName = @RoleName IF @Count = 0 INSERT INTO Account_Role (CategoryID, RoleName, Description) valueS (@CategoryID, @RoleName, @Description) SET @RoleID = @@IDENTITY RETURN 1 GO
SqlConnection DbConnection = new SqlConnection(mConnectionString); SqlCommand command = new SqlCommand( "sp_AccountRole_Create", DbConnection ); DbConnection.Open(connectString); // 废置SqlCommand的属性为存储过程 command.CommandType = CommandType.StoredProcedure; command.Parameters.Add("@CategoryID", SqlDbType.Int, 4); command.Parameters.Add("@RoleName", SqlDbType.NVarChar, 10); command.Parameters.Add("@Description", SqlDbType.NVarChar, 50); command.Parameters.Add("@RoleID", SqlDbType.Int, 4); // 返回值 command.Parameters.Add("Returnvalue", SqlDbType.Int, 4, // Size ParameterDirection.Returnvalue, false, // is nullable 0, // byte precision 0, // byte scale string.Empty, DataRowVersion.Default, null ); command.parameters["@CategoryID"].value = permission.CategoryID; command.parameters["@RoleName"].value = permission.PermissionName; command.parameters["@Description"].value = permission.Description; // 可以返回新的ID值 command.parameters["@RoleID"].Direction = ParameterDirection.Output; int rowsAffected = command.ExecuteNonQuery(); int result = command.parameters["Returnvalue"].value; int newID = command.parameters["@RoleID"].value;
