C#

DataTable table = DataSet1.Tables["Orders"];<br />
    // Presuming the DataTable has a column named Date.<br />
    string expression;<br />
    expression = "Date > '1/1/00'";<br />
    DataRow[] foundRows;<br />
<br />
    // Use the Select method to find all rows matching the filter.<br />
    foundRows = table.Select(expression);<br />
<br />
    // Print column 0 of each returned row.<br />
    for(int i = 0; i < foundRows.Length; i ++)<br />
    {<br />
        Console.WriteLine(foundRows[i][0]);<br />

<br />
<br />
// flags to check if found<br />
bool testMatched, test1Matched, test2Matched, test4Matched;<br />
// by default none found<br />
testMatched = false;<br />
test1Matched = false;<br />
test2Matched = false;<br />
test4Matched = false;<br />
<br />
foundRows = datatable.Select("itemName='test' or itemName='test1' or itemName='test2' or itemName='test4'");<br />
<br />
// if any row found<br />
if(foundRows.Length > 0)<br />
{<br />
// loop through all found rows<br />
for(int i=0; i<foundRows.Length; i++)<br />
{<br />
// check what found<br />
// and set mached flag to true<br />
switch(foundRows[i]["itemName"])<br />
{<br />
case "test":<br />
testMatched = true;<br />
break;<br />
case "test1":<br />
test1Matched = true;<br />
break;<br />
case "test2":<br />
test2Matched = true;<br />
break;<br />
case "test4":<br />
test4Matched = true;<br />
break;<br />
}<br />
}<br />
}<br />
<br />
// now here you can check that whatever flag is false that did not found in the result <br />
//for exmaple<br />
if(!testMatched)<br />
 Response.Write("Test did not found");<br />