how to convert this c# to vb.net

[sagey]

		public virtual User this[string Username] 
		{
			get 
			{
				int index = -1;
				for (int i=0; i<this.List.Count; i++)
				{
					if (((User)this.List[i]).UserName==Username)
					{
						index = i;
					}
				}
				if (index==-1){throw new NullReferenceException ("The User " + Username + " was not found.");}
				if (!((User)this.List[index]).IsLoaded)
				{
					((User)this.List[index]).Load();
				}
				return (User) this.List[index];
			}
			set 
			{
				int index = -1;
				for (int i=0; i<this.List.Count; i++)
				{
					if (((User)this.List[i]).UserName==Username)
					{
						index = i;
					}
				}
				if (index==-1){throw new NullReferenceException ("The User " + Username + " was not found.");}
				this.List[index] = value;
			}
		}