Preventing SQL Injection

I am building my first ASP.Net app from scratch and while working on the DAL I came across the problem of SQL Injection. I searched on the web and read different articles but I am still unsure about the answer. My question is should I add

db.AddInParameter(dbCommand, "AvatarImageID", DbType.Int32, avatarImageID);

Add in Parameters to my C# code to avoid SQL Injection. What is the best practice. I am unclear if the stored procedure already helps me avoid SQl Injection or if I need the add in parameters in the C# methods to make it work. I need some help. Thanks, Newbie

My C# update method in the DAL (still working on the code)

private static bool Update(AvatarImageInfo avatarImage)
{
//Invoke a SQL command and return true if the update was successful.
db.ExecuteNonQuery("syl_AvatarImageUpdate",
avatarImage.AvatarImageID,
avatarImage.DateAdded,
avatarImage.ImageName,
avatarImage.ImagePath,
avatarImage.IsApproved);

return true;
}


I am using stored procedures to access the data in the database.

My update stored proc

set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON
GO

ALTER PROCEDURE [dbo].[syl_AvatarImageUpdate]
@AvatarImageIDint,
@DateAddeddatetime,
@ImageNamenvarchar(64),
@ImagePathnvarchar(64),
@IsApprovedbit
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
BEGIN TRY
UPDATE[syl_AvatarImages]
SET
[DateAdded]= @DateAdded,
[ImageName]= @ImageName,
[ImagePath]= @ImagePath,
[IsApproved]= @IsApproved
WHERE[AvatarImageID] = @AvatarImageID
RETURN
END TRY
BEGIN CATCH
--Execute LogError SP
EXECUTE [dbo].[syl_LogError];
--Being in a Catch Block indicates failure.
--Force RETURN to -1 for consistency (other return values are generated, such as -6).
RETURN -1
END CATCH
END