QlikTip #31: Access Qvd Meta Data programmatically without using QlikView but pure .net & C#

This article shows you how you can access the xml header of a Qvd file without using QlikView programmatically using just .net & C#:

Every Qvd file in QlikView has a XML header (which you can easily prove by opening any Qvd file using a standard text editor):

There are several function available for usage withing QlikView load scripts for accessing these meta data:

QvdCreateTime(filename)
QvdNoOfRecords(filename)
QvdNoOfFields(filename)
QvdFieldName(filename , fieldno)
QvdTableName(filename)

Using these functions within a sample

[qvl]
// QlikView load script
Set a = ‘D:\QlikView\Transactions.qvd’;

LET vFileSize = FileSize(a);
LET vQvdCreateTime = QvdCreateTime(a);
LET vQvdNoOfRecords = QvdNoOfRecords(a);
LET vQvdNoOfFields = QvdNoOfFields(a);
LET vQvdFieldName = QvdFieldName(a, 1);
LET vQvdTableName = QvdTableName(a);

TRACE –;
TRACE FileSize: $(vFileSize);
TRACE QvdNoOfRecords: $(vQvdNoOfRecords);
TRACE QvdNoOfFields: $(vQvdNoOfFields);
TRACE QvdFieldName(1): $(vQvdFieldName);
TRACE QvdTableName: $(vQvdTableName);
TRACE –;
[/qvl]

would result into:

Result of reading the qvd header within a QlikView load script

Certainly, for accessing these functions you have to use QlikView, but I wanted to be able to achieve the same results outside of QlikView.
So I’ve created a little .net (2.0) based library which you can use in your projects:

Class diagramm of the C# library for reading the Qvd headers

Using the class QvdMetaInfos is easy (example in C#):

foreach (FileInfo file in new DirectoryInfo(@"C:\\QlikView\").GetFiles("*.qvd"))
{
         QlikLibs.QvdMetaInfos qvdInfos = new QlikLibs.QvdMetaInfos(file.FullName);
         Console.WriteLine("File:\t\t" + qvdInfos.QvdFileName);
         Console.WriteLine("QvdNoOfRecords:\t" + qvdInfos.QvdNoOfRecords.ToString());
         Console.WriteLine("QvdNoOfFields:\t" + qvdInfos.QvdNoOfFields.ToString());
         Console.WriteLine("QvdTableName:\t" + qvdInfos.QvdTableName);
         Console.WriteLine("");
         Console.WriteLine("Fields:");

         foreach (QlikLibs.QvdField qvdField in qvdInfos.QvdFields)
         {
              Console.Write("\t\t" + qvdField.FieldName);
              Console.Write(" (" + qvdField.NumberFormat.Type + ")\n");                
         }
         System.Console.Read();
}

The result:

Result of testing the library with a console application