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Generate Random Password in ASP.NET

Here, we will see how to generate random passwords in ASP.NET. Random numbers may be generated in the .NET Framework using the Random class. You create an instance of an object of a Random class and generate random numbers. You have to create a website and add a new page to the website. Drag and drop two TextBox and one Button control on the form. One TextBox gives the length of the TextBox, and another displays the random password of the specified length when we click on the Button control. Let's take a look at a practical example.

First, you have to create a website.

  • Go to Visual Studio 2010
  • New-> Select a website application
  • Click OK
    Website application

Now add a new page to the website.

  • Go to the Solution Explorer
  • Right Click on the Project name
  • Select add a new item
  • Add a new web page and give it a name
  • Click OK
    Solution Explorer

Now create a new website and drag and drop two TextBox controls onto the aspx page. The TextBox code looks like this.

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="randomnumber.aspx.cs" Inherits="randomnumber" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
        <div>
            Password Length: &nbsp;&nbsp;
            <asp:TextBox ID="txtPassLength" runat="server"></asp:TextBox>
            <br />
            Random Password: <asp:TextBox ID="txtpassword" runat="server" ReadOnly="true"></asp:TextBox>
            <br />
            <br />
            <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Generate Password" />
            <br />
        </div>
    </form>
</body>
</html>

In ASP.Net you can use a Random class to generate the random numbers. Create an instance of an object of the Random class and generate random numbers. This class may be instantiated using the following code.

Random rand = new Random();

In the above rand is an object of the Random Class.

Now double-click on the Button control and add the following code.

C# code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class randomnumber : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        string allowedChars = "";
        allowedChars = "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,";
        allowedChars += "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,";
        allowedChars += "1,2,3,4,5,6,7,8,9,0,!,@,#,$,%,&,?";

        char[] sep = { ',' };
        string[] arr = allowedChars.Split(sep);

        string passwordString = "";
        string temp = "";
        Random rand = new Random();

        for (int i = 0; i < Convert.ToInt32(txtPassLength.Text); i++)
        {
            temp = arr[rand.Next(0, arr.Length)];
            passwordString += temp;
        }

        txtpassword.Text = passwordString;
    }
}

Now run the application and test it.

Run the application

Now give the length of the password.

Generate password

Now click on the Button to generate a random password.

Random password

The above output displays a random password.

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