String cannot be of zero length. Parameter name: oldV

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Hi all,

i got some errors while am creating search option in my application , in this am handling asp.net application using c#.The thing is i enter some text in my textbox and i click search button its working fine, but without entering anything in the textbox and click search button ,its showing following error,

"String cannot be of zero length.
Parameter name: oldV "

click event code,

C#

protected void imgSearch_Click(object sender, ImageClickEventArgs e)
{
   Session.Add("searchterm", txtSearch.Text.Trim());
   Response.Redirect("cheers_search-result.aspx");
}

please see my below source code and let me know if any solution

C#

clsOleCon objOle = new clsOleCon();
System.Text.StringBuilder strtodisplay = new System.Text.StringBuilder();
protected void Page_Load(object sender, EventArgs e)
{
   string searchterm = Session["searchterm"].ToString();
   string query = "SELECT * from content where contents like '%" + searchterm + "%';";
   DataTable dt = objOle.selectquery(query);

   if (dt.Rows.Count > 0)
   {
      strtodisplay.Append("<table width=95% border=0 align=center cellpadding=0 cellspacing=0 class="top-8">");
      foreach (DataRow dr in dt.Rows)
      {
         string resultant = "";
         if (dr.ItemArray[1].ToString().Length > 150)
         {
            resultant = dr.ItemArray[1].ToString().Remove(150, (dr.ItemArray[1].ToString().Length - 150));

            resultant = resultant.ToLower();
            resultant = resultant.Replace(searchterm, "<Span class="searchtext_cheers">" + searchterm + "</span>");
            // resultant = resultant.Replace(searchterm, "<Span class="searchtext">" + searchterm + "</span>");

         }
         else
         {
            resultant = dr.ItemArray[1].ToString();
            resultant = resultant.Replace(searchterm, "<Span class="searchtext_cheers">" + searchterm + "</span>");
         }
         resultant = resultant + " ....";

         strtodisplay.Append("<tr><td width=95%>");
         strtodisplay.Append("<a href=" + dr.ItemArray[2].ToString() + ">");
         strtodisplay.Append("<span class="footer">" + resultant + "</span>");
         strtodisplay.Append("</a>");
         strtodisplay.Append("</td></tr>");
         strtodisplay.Append("<tr><td width=95% class="searchlink_cheers"><a  class="searchlink_cheers" href=" + dr.ItemArray[2].ToString() + ">" + dr.ItemArray[2].ToString() + "</a></td></tr>");
         strtodisplay.Append("<tr><td width=95%>&nbsp;</td></tr>");
      }
      strtodisplay.Append("</table>");
      lblSearchresult.Text = strtodisplay.ToString();
   }
   else
   {
      strtodisplay.Append("<table width=100% border=0 align=center cellpadding=0 cellspacing=0 class="top-8"><tr><td width=100%  class="searchresult_nomatch">");
      strtodisplay.Append("No Matches found");
      strtodisplay.Append("</td></tr></table>");
      lblSearchresult.Text = strtodisplay.ToString();
   }
}

thanks in advance

Posted 4-Jan-13 4:05am

stellus

Updated 4-Jan-13 4:10am

fjdiewornncalwe

v2

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fjdiewornncalwe · Answer 1 · 2013-01-04T04:14:00

Solution 1

The problem will lie with the line Session.Add("searchterm", txtSearch.Text.Trim());
You need to do something like this because Session values can't be string.Empty.

C#

if( !string.IsNullOrEmpty(txtSearch.Text.Trim()) )
{
   Session.Add("searchterm", txtSearch.Text.Trim());
}
else
{
   // You could either remove search term from the Session if there isn't one, or set a default value.
}

Posted 4-Jan-13 4:14am

fjdiewornncalwe

Comments

stellus 5-Jan-13 7:02am

thank u very much the code which u provide is workin fine,

Jibesh 6-Jan-13 14:31pm

If this solution works you can mark this solution as resolved.

Jibesh 6-Jan-13 14:30pm

my 5+

fjdiewornncalwe 7-Jan-13 9:08am

Thanks, jibesh.

Zafar Sultan · Answer 2 · 2013-01-04T04:15:00

Solution 2

Are you sure when the query text is parsed to

SQL

SELECT * from content where contents like '%%'

will fetch you any result? You should try adding client side validation for blank string or add a condition in your query that if the string is blank return all result.

Posted 4-Jan-13 4:15am

Zafar Sultan