vb.net随机函数 vb中随机函数

'********************************
'随机函数生成
'输入值：生成值范围 fromNum～toNum
'返回值：随机数
'********************************

Public Function Get_RandNum(fromNum,toNum)
  If (fromNum<0) Or (toNum<0) Then
   MsgBox "只接受大于零的输入"
  ElseIf fromNum>toNum then
   MsgBox "起始值必须小于结束值"
  Else
   Dim RunTime
   Randomize  
   RunTime = Int((10 * Rnd) + 1)
   Dim MyValue,i
   For i = 1 To RunTime
    Randomize 
    MyValue = Int(((toNum - fromNum + 1) * Rnd) + (fromNum))
   Next
     Get_randNum=MyValue
    End If
 End Function 
'********************************
 '随机生成（数字）
 '********************************
 Function MakeOnlyNum(inputlength)
  Dim I,x,B,A
  If IsNumeric(inputlength) Then
  For I = 1 To inputlength
   A = Array("0","1","2","3","4","5","6","7","8","9")
   Randomize
   x=Get_RandNum(0,9)
   B = A(x)
   MakeOnlyNum =MakeOnlyNum +B
  Next
   MakeOnlyNum = MakeOnlyNum
  else
   msgbox ("只接受数字输入")
  End If
 End Function 
'********************************
 '随机生成（字符串+数字）
 '********************************
 Function MakeString(inputlength)
  Dim I,x,B,A
  If IsNumeric(inputlength) Then
  For I = 1 To inputlength
   A = Array("0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z")
   Randomize
   x=Get_RandNum(0,35)
   B = A(x)
   makestring =makestring +B
  Next
   MakeString = makestring
  else
   msgbox ("只接受数字输入")
  End If
 End Function 
'********************************
 '随机生成（字符串）
 '********************************
 Function MakeOnlyString(inputlength)
  Dim I,x,B,A
  If IsNumeric(inputlength) Then
  For I = 1 To inputlength
   A = Array("a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z")
   Randomize
   x=Get_RandNum(0,25)
   B = A(x)
   MakeOnlyString =MakeOnlyString +B
  Next
   MakeOnlyString = MakeOnlyString
  else
   msgbox ("只接受数字输入")
  End If
 End Function