[c#] How to pass a null variable to a SQL Stored Procedure from C#.net code

Im calling a SQL stored procedure from a piece of C#.net code:

SqlHelper.ExecuteDataset(sqlConnection, CommandType.StoredProcedure, STORED_PROC_NAME, sqlParameters);

where the sqlParameters variable is defined as:

        SqlParameter[] sqlParameters = new SqlParameter[SQL_NUMBER_PARAMETERS];

        Log.Logger.Debug(string.Format("Running proc: {0} ", STORED_PROC_NAME));

        SqlParameters[0] = new SqlParameter("fieldID", SqlDbType.BigInt );
        SqlParameters[0].Value = fieldID;
        SqlParameters[0].Direction = ParameterDirection.Input;

I need to now pass in another two parameters to this Stored Proc, (both are of type SqlDateTime), which are going to NULL in this case.

Thanks,

IN

    SQLParam = cmd.Parameters.Add("@RetailerID", SqlDbType.Int, 4)
    If p_RetailerID.Length = 0 Or p_RetailerID = "0" Then
        SQLParam.Value = DBNull.Value
    Else
        SQLParam.Value = p_RetailerID
    End If

You can pass the DBNull.Value into the parameter's .Value property:

    SqlParameters[0] = new SqlParameter("LedgerID", SqlDbType.BigInt );
    SqlParameters[0].Value = DBNull.Value;

Just adjust for your two DateTime parameters, obviously - just showing how to use the DBNull.Value property value here.

Marc

Let's say the name of the parameter is "Id" in your SQL stored procedure, and the C# function you're using to call the database stored procedure is name of type int?. Given that, following might solve your issue :

public void storedProcedureName(Nullable<int> id, string name)
{
    var idParameter = id.HasValue ?
                new SqlParameter("Id", id) :
                new SqlParameter { ParameterName = "Id", SqlDbType = SqlDbType.Int, Value = DBNull.Value };

    // to be continued...

Old question, but here's a fairly clean way to create a nullable parameter:

new SqlParameter("@note", (object) request.Body ?? DBNull.Value);

If request.Body has a value, then it's value is used. If it's null, then DbNull.Value is used.

I use a method to convert to DBNull if it is null

    // Converts to DBNull, if Null
    public static object ToDBNull(object value)
    {
        if (null != value)
            return value;
        return DBNull.Value;
    }

So when setting the parameter, just call the function

    sqlComm.Parameters.Add(new SqlParameter("@NoteNo", LibraryHelper.ToDBNull(NoteNo)));

This will ensure any nulls, get changed to DBNull.Value, else it will stay the same.

Use DBNull.Value Better still, make your stored procedure parameters have defaults of NULL. Or use a Nullable<DateTime> parameter if the parameter will sometimes be a valid DateTime object

try this! syntax less lines and even more compact! don't forget to add the properties you want to add with this approach!

cmd.Parameters.Add(new SqlParameter{SqlValue=(object)username??DBNull.Value,ParameterName="user" }  );