How do i change property value in vb.net - vb.net

Question

i would like to assign my array vals to properties of my object.
like:
For i = 1 To 32
myClass.Prop_i = val[i]
Next

Answer 1

VB.NET isn't a dynamic language: you can't do such things.
Since VB.NET doesn't have a "dynamic" keyword like C#, your option is reflection:
myClass.GetType().GetProperty("Prop_" + i.ToString()).SetValue(myClass, val[i], null);
But if you're more explicit with your problem maybe there's a more elegant solution than reflection ;)

Answer 2

Your property needs to define Set. This will allow you to modify the property.

Answer 3

If you are willing to write some code in C# and use it in VB.NET, and need to store primitive types like int, float or byte, and all your properties are of the same type. Then you can create a union structure with an array covering the fields.
Then you can use code like this:
Sub Main() ' vb.net
Dim bag As New PropertyBag()
bag.AllProperties = New Single() {1, 2, 3, 4, 5, 6, 7, 8}
Dim three As Single = bag.Prop_3 'returns 3
Dim five As Single = bag(4) 'returns 5 (0-based index)
End Sub
When declared like
[StructLayout(LayoutKind.Explicit, Size=Size)]
public unsafe struct PropertyBag
{
const int Count = 8; //8 fields
const int Size = 8 * 4; //4 bytes per field
[FieldOffset(0)]
fixed float list[Count];
[FieldOffset(0)] float x1;
[FieldOffset(4)] float x2;
[FieldOffset(8)] float x3;
[FieldOffset(12)] float x4;
[FieldOffset(16)] float x5;
[FieldOffset(20)] float x6;
[FieldOffset(24)] float x7;
[FieldOffset(28)] float x8;
public float Prop_1 { get { return x1; } set { x1 = value; } }
public float Prop_2 { get { return x2; } set { x2 = value; } }
public float Prop_3 { get { return x3; } set { x3 = value; } }
public float Prop_4 { get { return x4; } set { x4 = value; } }
public float Prop_5 { get { return x5; } set { x5 = value; } }
public float Prop_6 { get { return x6; } set { x6 = value; } }
public float Prop_7 { get { return x7; } set { x7 = value; } }
public float Prop_8 { get { return x8; } set { x8 = value; } }
public float this[int index]
{
get
{
fixed (float* ptr = list)
{
return ptr[index];
}
}
set
{
fixed (float* ptr = list)
{
ptr[index] = value;
}
}
}
public float[] AllProperties
{
get
{
float[] res = new float[Count];
fixed (float* ptr = list)
{
for (int i = 0; i < Count; i++)
{
res[i] = ptr[i];
}
}
return res;
}
set
{
fixed (float* ptr = list)
{
for (int i = 0; i < Count; i++)
{
ptr[i] = value[i];
}
}
}
}
}
Note that reflection should work in your case (like others have answered), but this is just a different approach to the problem (and a very fast one too). The main limitation is what types can be made into pointers in C# (sbyte, byte, short, ushort, int, uint, long, ulong, char, float, double, decimal, or bool)