C# equivalent of the IsNull() function in SQL Server

Question

In SQL Server you can use the IsNull() function to check if a value is null, and if it is, return another value. Now I am wondering if there is anything similar

Answer 1

    public static T IsNull(this T DefaultValue, T InsteadValue)
    {

        object obj="kk";

        if((object) DefaultValue == DBNull.Value)
        {
            obj = null;
        }

        if (obj==null || DefaultValue==null || DefaultValue.ToString()=="")
        {
            return InsteadValue;
        }
        else
        {
            return DefaultValue;
        }

    }

//This method can work with DBNull and null value. This method is question's answer