Working with Redim Statement in VB.Net and its Advantages
It is use to declare dynamic-array variables and allocate or reallocate storage space. This is a very use full statement of VB.Net and we can declare dynamic arrays with this.
The ReDim statement is used to size or resize a dynamic array that has already been formally declared using a Private, Public, or Dim statement with empty parentheses (without dimension subscripts). You can use the ReDim statement repeatedly to change the number of elements and dimensions in an array.
If you use the Preserve keyword, you can resize only the last array dimension, and you can't change the number of dimensions at all. For example, if your array has only one dimension, you can resize that dimension because it is the last and only dimension. However, if your array has two or more dimensions, you can change the size of only the last dimension and still preserve the contents of the array. The following example shows how you can increase the size of the last dimension of a dynamic array without erasing any existing data contained in the array.
ReDim [Preserve] varname(subscripts) [, varname(subscripts)] . . .
Preserves the data in an existing array when you change the size of the last dimension
Name of the variable; follows standard variable naming conventions.
Dimensions of an array variable; up to 60 multiple dimensions may be declared. The subscripts argument uses the following syntax:
upper [,upper] . . .
The lower bound of an array is always zero.