Select Distinct from DataTable

public DataSet ds = new DataSet();

DataTable dtDate = SelectDistinct("aaa", dt, "Date");

public DataTable SelectDistinct(string TableName, DataTable SourceTable, string FieldName)
{
DataTable dt = new DataTable(TableName);
dt.Columns.Add(FieldName, SourceTable.Columns[FieldName].DataType);

object LastValue = null;
foreach (DataRow dr in SourceTable.Select("", FieldName))
{
if (LastValue == null || !(ColumnEqual(LastValue, dr[FieldName])))
{
LastValue = dr[FieldName];
dt.Rows.Add(new object[] { LastValue });
}
}
if (ds != null)
ds.Tables.Add(dt);
return dt;
}
private bool ColumnEqual(object A, object B)
{

// Compares two values to see if they are equal. Also compares DBNULL.Value.
// Note: If your DataTable contains object fields, then you must extend this
// function to handle them in a meaningful way if you intend to group on them.

if (A == DBNull.Value && B == DBNull.Value) // both are DBNull.Value
return true;
if (A == DBNull.Value || B == DBNull.Value) // only one is DBNull.Value
return false;
return (A.Equals(B)); // value type standard comparison
}

Impersonation webconfig

<system.web>
<identity impersonate="true" username="Domain\username" password="password">
</system.web>

Impersonation Programmatically

public const int LOGON32_LOGON_INTERACTIVE = 2;
public const int LOGON32_PROVIDER_DEFAULT = 0;

WindowsImpersonationContext impersonationContext;

[DllImport("advapi32.dll")]
public static extern int LogonUserA(String lpszUserName,
String lpszDomain,
String lpszPassword,
int dwLogonType,
int dwLogonProvider,
ref IntPtr phToken);
[DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern int DuplicateToken(IntPtr hToken,
int impersonationLevel,
ref IntPtr hNewToken);

[DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool RevertToSelf();

[DllImport("kernel32.dll", CharSet = CharSet.Auto)]
public static extern bool CloseHandle(IntPtr handle);


private bool impersonateValidUser(String userName, String domain, String password)
{
WindowsIdentity tempWindowsIdentity;
IntPtr token = IntPtr.Zero;
IntPtr tokenDuplicate = IntPtr.Zero;

if (RevertToSelf())
{
if (LogonUserA(userName, domain, password, LOGON32_LOGON_INTERACTIVE,
LOGON32_PROVIDER_DEFAULT, ref token) != 0)
{
if (DuplicateToken(token, 2, ref tokenDuplicate) != 0)
{
tempWindowsIdentity = new WindowsIdentity(tokenDuplicate);
impersonationContext = tempWindowsIdentity.Impersonate();
if (impersonationContext != null)
{
CloseHandle(token);
CloseHandle(tokenDuplicate);
return true;
}
}
}
}
if (token != IntPtr.Zero)
CloseHandle(token);
if (tokenDuplicate != IntPtr.Zero)
CloseHandle(tokenDuplicate);
return false;
}

private void undoImpersonation()
{
impersonationContext.Undo();
}

BindData()

{

if (impersonateValidUser("abc", "abc", "abc"))
{

//work
undoImpersonation();

}
}

Conversion of Datarow [] to Datatable

dt = new DataTable();
dt.Columns.Add("Industries", typeof(string));
dt.Columns.Add("Project", typeof(string));
dt.Columns.Add("FolderName", typeof(string));
dt.Columns.Add("FolderPath", typeof(string));
dt.Columns.Add("Date", typeof(string));

foreach (DataRow dr in dto)
{
dt.ImportRow(dr);
}
dt.AcceptChanges();

dt.Select(Date Filter)

string filter = "[Date] >= '" + Convert.ToDateTime(txtTo.Text).ToShortDateString() + "' AND [Date] <= '" + Convert.ToDateTime(txtFrom.Text).ToShortDateString() + "'";

DataRow[] dto = notDownloaded.Select(filter);
//DataRow[] dto = notDownloaded;