C#

foreach (string item in sourceString)
     if (sourceString.Contains(item))
     {
          //do what you want when you hit an item
          //from the listbox in your sourceString
     }

using System;<br />
using System.Collections.Generic;<br />
using System.ComponentModel;<br />
using System.Data;<br />
using System.Drawing;<br />
using System.Text;<br />
using System.Windows.Forms;<br />
<br />
namespace WindowsApplication1<br />
{<br />
    public partial class Form1 : Form<br />
    {<br />
        public Form1()<br />
        {<br />
            InitializeComponent();<br />
        }<br />
<br />
        private void button1_Click(object sender, EventArgs e)<br />
        {<br />
            //see if textbox1.text is found, in part or whole, against the items in the listbox<br />
            foreach(string item in listBox1.Items)<br />
            {<br />
                if (item.ToString().Contains(textBox1.Text))<br />
                {<br />
                    textBox2.Text += ("Substring found in entry " + item.ToString() + "\r\n");<br />
                }<br />
                <br />
            }<br />
        }<br />
    }<br />
}<br />

M. Nauman Yousuf wrote:

Is there any way that we can check if a specific variable is declared or not

if(string.IsNullOrEmpty(Request.QueryString["myVariable"]))
{
  // the variable does not exist in the URL
}

J4amieC wrote:

if(string.IsNullOrEmpty(Request.QueryString["myVariable"]))
{
// the variable does not exist in the URL
}

if (Request.QueryString["myVariable"] == null) {
   // the variable does not exist in the URL
}

if (string.IsNullOrEmpty(Request.QueryString["myVariable"])) {
   // the variable does not exist in the URL, or is empty
}

M. Nauman Yousuf wrote:

Is there any way that we can check if a specific variable is declared or not