C#

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

<br />
char[] arrChars = txtASCII.Text.ToCharArray();<br />
                String sBinary = "";<br />
                String D;<br />
                D = " ";<br />
                foreach (char ch in arrChars)<br />
                {<br />
                    sBinary += Convert.ToString(Convert.ToInt32(ch),2) + D;<br />
                }<br />
                txtBIN.Text = sBinary;<br />

int intValue=123;
string strDecimal=intValue.ToString();     // yields "123"
string strHex=intValue.ToString("X2");     // yields "7B"
string strHey=intValue.ToString("X4");     // yields "007B"

string str="12345";
int myDecimal=int.Parse(str);      // yields the number 12345
byte overfl=byte.Parse(str);       // throws some overflow exception
int myHex=int.Parse(str,NumberStyles.AllowHexSpecifier);  // yields integer 74565 (was hex !)
    // and yes the AllowHexSpecifier is a misnomer

<br />
string[] arrStrings = this.txtBIN.Text.Trim(' ').Split(' ');<br />
                String sText = "";<br />
                foreach (string st in arrStrings)<br />
                    sText += Convert.ToChar(Convert.ToInt32(st, 2));<br />
                this.txtTEXT.Text = sText;<br />