کد جستجو در سی شارپ دیتا گرید ویو find

string[] columnName = new string[20];

columnName[0] = dt.Columns["Name"].ColumnName;
columnName[1] = dt.Columns["Family"].ColumnName;
columnName[2] = dt.Columns["idPerson"].ColumnName;

public string resaultOfSearch1(DataTable rdt , string txt , string[] listColumn)
{
}

if (txt != "")
{
}

if (txt != "")
{
try
{
int x = Convert.ToInt32(txt);
items = string.Empty;
}
catch (Exception)
{
}
}

try
 {
 int x = Convert.ToInt32(txt); items = string.Empty;
 for (int i = 0; i < rdt.Columns.Count; i++)
 {
 if (Array.IndexOf(listColumn, rdt.Columns[i].ToString()) != -1)
 {
 if (rdt.Columns[i].DataType == typeof(Int32)) 
{ 
if (i == rdt.Columns.Count - 1) { items += rdt.Columns[i] + "=" + txt;
 }
 else
 {
 items += rdt.Columns[i] + "=" + txt + " OR ";
 }
 } 
else if (rdt.Columns[i].DataType == typeof(string)) 
{
 if (i == rdt.Columns.Count - 1)
 {
 items += rdt.Columns[i] + " LIKE '%" + txt + "%'"; 
} 
else
 {
 items += rdt.Columns[i] + " LIKE '%" + txt + "%'" + " OR ";
 }
 }
 }
 }
 }

catch (Exception) 
{
 try
 {
 items = string.Empty;
 for (int i = 0; i < rdt.Columns.Count; i++) 
{
 if (Array.IndexOf(listColumn, rdt.Columns[i].ToString()) != -1) 
{
 if (rdt.Columns[i].DataType == typeof(string))
 {
 if (i == rdt.Columns.Count)
 {
 items += rdt.Columns[i] + " LIKE '%" + txt + "%'"; 
} 
else
 {
 items += rdt.Columns[i] + " LIKE '%" + txt + "%'" + " OR ";
 }
 }
 }
 }
 }
 catch (Exception) { } 
}

private void textBox4_TextChanged(object sender, EventArgs e)
{
Class.search1 srch1 = new Class.search1();
dt.DefaultView.RowFilter = srch1.resaultOfSearch1(dt,textBox4.Text,columnName);
}