Try this.
private void GetRowsByFilter()
{
var DataSet1 = new DataSet();
var table1 = new DataTable("Orders");
DataSet1.Tables.Add(table1);
var table = DataSet1.Tables["Orders"];
table.Columns.Add(new DataColumn { Caption = "Transction type", ColumnName = "Transctiontype", DataType = typeof(string) });
table.Columns.Add(new DataColumn { Caption = "Transaction category", ColumnName = "Transactioncategory", DataType = typeof(string) });
table.Columns.Add(new DataColumn { Caption = "Date", ColumnName = "Date", DataType = typeof(DateTime) });
table.Columns.Add(new DataColumn { Caption = "Amount", ColumnName = "Amount", DataType = typeof(int) });
table.Columns.Add(new DataColumn { Caption = "Vendor", ColumnName = "Vendor", DataType = typeof(string) });
var newRw = table.NewRow();
newRw["Transctiontype"] = "Life style";
newRw["Date"] = DateTime.Now;
newRw["Amount"] = 1000;
newRw["Vendor"] = "Net play";
table.Rows.Add(newRw.ItemArray);
newRw = table.NewRow();
newRw["Transctiontype"] = "Non Life style";
newRw["Date"] = DateTime.Now;
newRw["Amount"] = 15000;
newRw["Vendor"] = "Microsoft";
table.Rows.Add(newRw.ItemArray);
newRw = table.NewRow();
newRw["Transctiontype"] = "Life style";
newRw["Date"] = DateTime.Now;
newRw["Amount"] = 15000;
newRw["Vendor"] = "CodeProject";
table.Rows.Add(newRw.ItemArray);
string expression;
expression = "Amount = 1000 and Transctiontype = 'Life style' and vendor = 'Net play'";
DataRow[] foundRows;
foundRows = table.Select(expression);
if (foundRows.Any())
{
}
}