Hi George616,
To avoid repeat number save the generated number as list in session and check the list while generating new number.
Once the work done clear the Session.
Refer below code.
HTML
<asp:Button Text="Generate Number" runat="server" OnClick="OnDistinctNumber" />
<hr />
<asp:Label ID="lblNumber" runat="server" />
Code
C#
protected void OnDistinctNumber(object sender, EventArgs e)
{
List<string> result = new List<string>();
if (Session["Numbers"] != null)
{
result = (List<string>)Session["Numbers"];
}
string number = GetAutoNumber();
if (!result.Contains(number))
{
result.Add(number);
Session["Numbers"] = result;
lblNumber.Text = number;
}
}
private string GetAutoNumber()
{
string numbers = "1234567890";
string characters = numbers;
int length = 7;
string id = string.Empty;
for (int i = 0; i < length; i++)
{
string character = string.Empty;
do
{
int index = new Random().Next(0, characters.Length);
character = characters.ToCharArray()[index].ToString();
} while (id.IndexOf(character) != -1);
id += character;
}
return id;
}
VB.Net
Protected Sub OnDistinctNumber(ByVal sender As Object, ByVal e As EventArgs)
Dim result As List(Of String) = New List(Of String)()
If Session("Numbers") IsNot Nothing Then
result = CType(Session("Numbers"), List(Of String))
End If
Dim number As String = GetAutoNumber()
If Not result.Contains(number) Then
result.Add(number)
Session("Numbers") = result
lblNumber.Text = number
End If
End Sub
Private Function GetAutoNumber() As String
Dim numbers As String = "1234567890"
Dim characters As String = numbers
Dim length As Integer = 7
Dim id As String = String.Empty
For i As Integer = 0 To length - 1
Dim character As String = String.Empty
Do
Dim index As Integer = New Random().Next(0, characters.Length)
character = characters.ToCharArray()(index).ToString()
Loop While id.IndexOf(character) <> -1
id += character
Next
Return id
End Function
