[need help] Filter records within Start and End Date of current year c#

I'm sorry if i am on the wrong section.

SCENARIO:
i am creating an asp.net page where  i use radio buttons for the current year, current month, and week, as well as their previous and next values.

for the current month as well as next month and previous month, my output is just okay. but when i select the year options, i cannot return any values.

by the way, i display the results using GridView.



CODE SAMPLE:

//my query string
if (this.Radiotyear.Checked==true ||this.Radiotweek.Checked == true || this.Radiotmonth.Checked == true)
{
queryString = "SELECT trans.trans_code AS 'Confirmation #', customer.cust_fname AS 'First Name',customer.cust_lname AS 'Last Name', trans.tdate AS 'Schedule Date', trans.ttime AS 'Schedule Time', trans.site_id AS 'Schedule Site' FROM trans INNER JOIN customer ON trans.cust_idno=customer.cust_idno WHERE trans.tdate BETWEEN @searchdatetoday AND @searchdatetodayend ";
}

System.Data.SqlClient.SqlCommand sqlCmd = new System.Data.SqlClient.SqlCommand(queryString, con);

sqlCmd.Parameters.Add("@searchdatetoday", System.Data.SqlDbType.NVarChar).Value = optionhandler.Text;
sqlCmd.Parameters.Add("@searchdatetodayend", System.Data.SqlDbType.NVarChar).Value = optionhandlerend.Text;
 
//end of the query string

// the code behind current year radio button

protected void Radiotyear_CheckedChanged(object sender, EventArgs e)
  {
  if (this.Radiotyear.Checked == true)
  {
  DayOfWeek day = DateTime.Now.DayOfWeek;
  int days = day - DayOfWeek.Sunday;
  DateTime start = DateTime.Now.AddDays(-days);
  DateTime end = start.AddDays(6);
  DateTime nwstart = end.AddDays(1);
  DateTime nwend = end.AddDays(7);
  DateTime lwend = start.AddDays(-1);
  DateTime lwstart = lwend.AddDays(-6);
  DateTime mstart = new DateTime (.Now.Year, DateTime.Now.Month, 1);
  DateTime mend = mstart.AddMonths(1).AddDays(-1);
  DateTime nmstart = mstart.AddMonths(1);
  DateTime nmend = mstart.AddMonths(2).AddDays(-1);
  DateTime lmstart = mstart.AddMonths(-1);
  DateTime lmend = mstart.AddDays(-1);
  DateTime ystart = new DateTime (DateTime.Now.Year, 1, 1);
  DateTime yend = ystart.AddMonths(12).AddDays(-1);
  DateTime nystart = ystart.AddYears(1);
  DateTime nyend = ystart.AddYears(2).AddDays(-1);
  DateTime lystart = ystart.AddYears(-1);
  DateTime lyend = ystart.AddDays(-1);


  this.Radiotoday.Checked = false;
  this.Radiotomorrow.Checked = false;
  this.Radiotweek.Checked = false;
  this.Radionweek.Checked = false;
  this.Radiotmonth.Checked = false;
  this.Radionmonth.Checked = false;
  this.Radiocustom.Checked = false;
  this.Radionyear.Checked = false;
  this.Radioyesterday.Checked = false;
  this.Radiolweek.Checked = false;
  this.Radiolmonth.Checked = false;
  this.Radiolyear.Checked = false;
 
 

  this.optionhandler.Text = ystart.ToString("d");
  this.optionhandlerend.Text = yend.ToString("d");

  }
  }

//end of the year radio button code behind


// the code behind current month radio button
protected void Radiotmonth_CheckedChanged(object sender, EventArgs e)
  {
  if (this.Radiotmonth.Checked == true)
  {
  DayOfWeek day = DateTime.Now.DayOfWeek;
  int days = day - DayOfWeek.Sunday;
  DateTime start = DateTime.Now.AddDays(-days);
  DateTime end = start.AddDays(6);
  DateTime mstart = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1);
  DateTime mend = mstart.AddMonths(1).AddDays(-1);

  this.Radiotoday.Checked = false;
  this.Radiotomorrow.Checked = false;
  this.Radiotweek.Checked = false;
  this.Radionweek.Checked = false;
  this.Radiocustom.Checked = false;
  this.Radionmonth.Checked = false;
  this.Radiotyear.Checked = false;
  this.Radionyear.Checked = false;
  this.Radioyesterday.Checked = false;
  this.Radiolweek.Checked = false;
  this.Radiolmonth.Checked = false;
  this.Radiolyear.Checked = false;

 
  this.optionhandler.Text = mstart.ToString("d");
  this.optionhandlerend.Text = mend.ToString("d");
 
 
  }
  }

//end of the month radio button code behind




please show me the correct codes here, thanks, and more power