<<= Operator (Visual Basic)
Performs an arithmetic left shift on the value of a variable or property and assigns the result back to the variable or property.
The element on the left side of the <<= operator can be a simple scalar variable, a property, or an element of an array. The variable or property cannot be ReadOnly (Visual Basic). The <<= operator assigns the value on its right to the variable or property on its left.
Arithmetic shifts are not circular, which means the bits shifted off one end of the result are not reintroduced at the other end. In an arithmetic left shift, the bits shifted beyond the range of the result data type are discarded, and the bit positions vacated on the right are set to zero.
The << Operator (Visual Basic) can be overloaded, which means that a class or structure can redefine its behavior when an operand has the type of that class or structure. Overloading the << operator affects the behavior of the <<= operator. If your code uses <<= on a class or structure that overloads <<, be sure you understand its redefined behavior. For more information, see Operator Procedures (Visual Basic).