在存储过程调用中使用默认参数

Question

I have the following stored procedure

CREATE PROCEDURE [dbo].[usp_GetData]
@foo VARCHAR (20), @bar bit = 1
AS ...

This provides the correct result when called in SSMS.

EXEC dbo.usp_GetData @foo = 'Hellow World', @bar = 0

Although when calling within a C# application as per below

cmd.Parameters.Add(new SqlParameter("@foo", foo)); 
cmd.Parameters.Add(new SqlParameter("@bar", 0));

& is captured by the profiler as below.

exec dbo.usp_GetData @foo=N'Hello World',@bar=default

Does a parameter that overides the default have to be passed differently?

Answer 1

Use

cmd.Parameters.AddWithValue("@bar", 0)

This way you know you actually passing the value.

Answer 2

new SqlParameter("@bar", 0) triggers the wrong overload - string parameterName, SqlDbType dbType . The value ends up being not set.

You want the one that sets the value, so it's ought to be new SqlParameter("@bar", (object)0) .

This is why AddWithValue was introduced.

Answer 3

更好，更安全：

cmd.Parameters.Add("@bar", SqlDbType.NVarChar, 16, "bar");