/// <summary>
/// Receives a ReturnField, SearchExpression and field to be searched a as parameters. The function
/// looks up a value and returns the value of the ReturnField on a successful
/// search. The function maintains the last Order() of the view.
/// Please note that unlike the VFP Lookup() command this one receives the ReturnField and SearchField as strings.
/// </summary>
/// <example>
/// string cCustomer = vfpData.Lookup("cname", "60", "iid", oView)
/// </example>
/// <param name="tcReturnField"></param>
/// <param name="tcSearchExpression"></param>
/// <param name="tcSearchedField"></param>
/// <returns></returns>
public static string Lookup(string tcReturnField, string tcSearchExpression, string tcSearchedField, DataView toView)
{
string cRetVal = "";
//Capture the current order
string cOrder = VfpData.Order(toView);
try
{
//Set the order to the search order
VfpData.SetOrderTo(tcSearchedField, toView);
int nFoundRec = VfpData.Seek(tcSearchExpression, toView);
//If we find a record then get the return value
if (nFoundRec != -1)
{
cRetVal = toView.Table.Rows[nFoundRec][tcReturnField].ToString();
VfpData._Found = true;
}
}
finally
{
//Cleanup to reset the old order
toView.Sort = cOrder;
}
return(cRetVal);
}
/// <summary>
/// As ADO.NET does not support current position of cursors.
/// This functions performs the same action as that of a seek
/// </summary>
/// <param name="tcExpression"></param>
/// <param name="toView"></param>
/// <returns></returns>
public static int IndexSeek(string tcExpression, DataView toView)
{
return(VfpData.Seek(tcExpression, toView));
}