[SQL,C#] Why doesn't my procedure work properly from code?

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C#

SQL

T-SQL

I'm executing my procedures from my C# code, and for some reason I can't see their effects on the server's tables.
Is there anything else I need to do except for executing them? What could be the cause for this annoying problem?

EDIT:

This is an example for a procedure:

public void DetachEventFromClient(long eventId, int clientId)
{
    ProcedureEnum procedure = ProcedureEnum.EventToClient_RemoveMatch;
    object[] input = new object[] { eventId, clientId };
    
// The get procedure method creates a command, and adds the input parameters.
    using (SqlCommand command = GetProcedure(procedure, input))
    {
        connection.ExecuteNonQuery(command);
    }
}

My Get Procedure function (I have a collection storing all my procedures... along with their parameters. And in this "execution" I'm just creating the procedure's SqlCommand, and adding the values. The dictionary is parameter name to parameter definition (along with its type and size if necessary...)

public SqlCommand GetProcedure(object[] input)
        {
            if (input.Length != Input.Count)
                throw new ArgumentException("Number of parameters is incorrect.");

            // Create STORED PROCEDURE Sql command of this type.
            SqlCommand c = new SqlCommand(Name) { CommandType = CommandType.StoredProcedure };
            // Add Input Values
            foreach (KeyValuePair<string, SQLParameter> kvp in Input)
                c.Parameters.AddWithValue(kvp.Key, input[0]); // DAMN IT, I'M AN IDIOT!!! :S 10 HOURS!!!

            // Add the output parameters.
            foreach (KeyValuePair<string, SQLParameter> kvp in Output)
            {
                SqlParameter p;
                if (kvp.Value.HasSize)
                    p = new SqlParameter(kvp.Value.Name, kvp.Value.Type, kvp.Value.Size) { Direction = ParameterDirection.Output };
                else
                    p = new SqlParameter(kvp.Value.Name, kvp.Value.Type) { Direction = ParameterDirection.Output };
                c.Parameters.Add(p);
            }

            return c;
        }

public int ExecuteNonQuery(SqlCommand command, bool showException = true)
{
    try
    {
        // Open connection
        if(connection.State == ConnectionState.Closed)
            connection.Open();

        // Set command's connection.
        command.Connection = connection;

        // Execute the query
        int affectedRows = command.ExecuteNonQuery();

        // Close connection
        connection.Close();

        // Return
        return affectedRows;
    }
    catch (SqlException e)
    {
        if(showException)
            printException(e);
        return 0;
    }

The actual procedure that is being executed here is: (No reason that it wouldn't work from C#, don't you agree?)

ALTER PROCEDURE EventToClient_RemoveMatch
 (@EventID bigint,@ClientID int) AS
 BEGIN
 DELETE FROM _EventToClient WHERE EventID = @EventID AND ClientID = @ClientID
 END

Why wouldn't it work from C#? does it have anything to do with transactions? I'm not using any, I never thought it was necessary. Are they necessary? Sometimes only a single row is affected (removed) by the procedure run, and the rest are ignored.