How to: Change Cached Data in a Workbook on a Server

Applies to

The information in this topic applies only to the specified Visual Studio Tools for Office projects and versions of Microsoft Office.

Project type

  • Document-level projects

Microsoft Office version

  • Excel 2007

  • Excel 2003

For more information, see Features Available by Application and Project Type.

You can change data in the cache of a Microsoft Office Excel workbook that is part of a document-level Visual Studio Tools for Office project without running Excel. This makes it possible to change data in Excel workbooks that are stored on a server.

The code to change the data must be outside of the main Visual Studio Tools for Office project assembly that is associated with the document you are working with, for example in an ASP.NET Web page, a console application, or a Windows Forms application.

For step-by-step instructions for using the code example in this topic, see Walkthrough: Changing Cached Data in a Workbook on a Server.

Example

The following code example first creates an instance of a typed dataset named AdventureWorksLTDataSet. Next, the code uses the ServerDocument class to access a filled instance of the same typed dataset that is already cached in an Excel workbook, and then reads the data from the cached dataset into the local dataset. Finally, the code modifies the ListPrice value in each row of the local dataset, and then writes the changed data back into the cached dataset by using the Xml property.

Dim productDataSet As New AdventureWorksDataSet.AdventureWorksLTDataSet()
Dim workbookPath As String = System.Environment.GetFolderPath( _
    Environment.SpecialFolder.MyDocuments) & _
    "\AdventureWorksReport\bin\Debug\AdventureWorksReport.xlsx" 
Dim serverDocument1 As ServerDocument = Nothing 

Try
    serverDocument1 = New ServerDocument(workbookPath)
    Dim dataHostItem1 As CachedDataHostItem = _
        serverDocument1.CachedData.HostItems("AdventureWorksReport.Sheet1")
    Dim dataItem1 As CachedDataItem = dataHostItem1.CachedData("AdventureWorksLTDataSet")

    If dataItem1 IsNot Nothing Then
        Console.WriteLine("Before reading data from the cache dataset, the local dataset has " & _
            "{0} rows.", productDataSet.Product.Rows.Count.ToString())

        ' Read the cached data from the worksheet dataset into the local dataset. 
        Dim schemaReader As New System.IO.StringReader(dataItem1.Schema)
        Dim xmlReader As New System.IO.StringReader(dataItem1.Xml)
        productDataSet.ReadXmlSchema(schemaReader)
        productDataSet.ReadXml(xmlReader)

        Console.WriteLine("After reading data from the cache dataset, the local dataset has " & _
            "{0} rows.", productDataSet.Product.Rows.Count.ToString())

        ' Modify the prices of each product in the local dataset. 
        Dim row As AdventureWorksDataSet.AdventureWorksLTDataSet.ProductRow
        For Each row In productDataSet.Product.Rows
            If row.ProductCategoryID < 20 Then
                row.ListPrice = row.ListPrice + row.ListPrice * 0.1
            Else
                row.ListPrice = row.ListPrice - row.ListPrice * 0.1
            End If 
        Next row

        ' Write the modified local dataset to the worksheet dataset using the DiffGram format. 
        Dim stringIn As New System.Text.StringBuilder()
        Dim stringOut As New System.IO.StringWriter(stringIn)
        productDataSet.WriteXml(stringOut, System.Data.XmlWriteMode.DiffGram)
        dataItem1.Xml = stringIn.ToString()

        serverDocument1.Save()
        Console.WriteLine("The product prices have been modified.")
    Else
        Console.WriteLine("The data object is not found in the data cache.")
    End If 
Catch ex As System.IO.FileNotFoundException
    Console.WriteLine("The specified workbook does not exist.")
Catch ex As System.Xml.XmlException
    Console.WriteLine("The data object has invalid XML information.")
Finally 
    If Not (serverDocument1 Is Nothing) Then
        serverDocument1.Close()
    End If
    Console.WriteLine(vbLf & vbLf & "Press Enter to close the application.")
    Console.ReadLine()
End Try
AdventureWorksDataSet.AdventureWorksLTDataSet productDataSet =
    new AdventureWorksDataSet.AdventureWorksLTDataSet();
string workbookPath = System.Environment.GetFolderPath(
    Environment.SpecialFolder.MyDocuments) +
    @"\AdventureWorksReport\bin\Debug\AdventureWorksReport.xlsx";
ServerDocument serverDocument1 = null;

try
{
    serverDocument1 = new ServerDocument(workbookPath);
    CachedDataHostItem dataHostItem1 =
        serverDocument1.CachedData.HostItems["AdventureWorksReport.Sheet1"];
    CachedDataItem dataItem1 = dataHostItem1.CachedData["adventureWorksLTDataSet"];

    if (dataItem1 != null)
    {
        Console.WriteLine("Before reading data from the cache dataset, the local dataset has " +
            "{0} rows.", productDataSet.Product.Rows.Count.ToString());

        // Read the cached data from the worksheet dataset into the local dataset.
        System.IO.StringReader schemaReader = new System.IO.StringReader(dataItem1.Schema);
        System.IO.StringReader xmlReader = new System.IO.StringReader(dataItem1.Xml);
        productDataSet.ReadXmlSchema(schemaReader);
        productDataSet.ReadXml(xmlReader);

        Console.WriteLine("After reading data from the cache dataset, the local dataset has " +
            "{0} rows.", productDataSet.Product.Rows.Count.ToString());

        // Modify the prices of each product in the local dataset. 
        foreach (AdventureWorksDataSet.AdventureWorksLTDataSet.ProductRow row in 
                 productDataSet.Product.Rows)
        {
            if (row.ProductCategoryID < 20)
            {
                row.ListPrice = row.ListPrice + (row.ListPrice * (Decimal).10);
            }
            else
            {
                row.ListPrice = row.ListPrice - (row.ListPrice * (Decimal).10);
            }
        }

        // Write the modified local dataset to the worksheet dataset using the DiffGram format.
        System.Text.StringBuilder stringIn = new System.Text.StringBuilder();
        System.IO.StringWriter stringOut = new System.IO.StringWriter(stringIn);
        productDataSet.WriteXml(stringOut, System.Data.XmlWriteMode.DiffGram);
        dataItem1.Xml = stringIn.ToString();

        serverDocument1.Save();
        Console.WriteLine("The product prices have been modified.");
    }
    else
    {
        Console.WriteLine("The data object is not found in the data cache.");
    }
}
catch (System.IO.FileNotFoundException)
{
    Console.WriteLine("The specified workbook does not exist.");
}
catch (System.Xml.XmlException)
{
    Console.WriteLine("The data object has invalid XML information.");
}
finally
{
    if (serverDocument1 != null)
    {
        serverDocument1.Close();
    }

    Console.WriteLine("\n\nPress Enter to close the application.");
    Console.ReadLine();
}

Compiling the Code

The code example in this topic is designed to be used in a console application that has access to a class library project that defines a typed dataset, and an Excel workbook that is part of a document-level customization for Excel 2003 or Excel 2007. For step-by-step instructions for using the code, see Walkthrough: Changing Cached Data in a Workbook on a Server.

See Also

Tasks

Walkthrough: Changing Cached Data in a Workbook on a Server

How to: Cache Data for Use Offline or on a Server

How to: Retrieve Cached Data from a Workbook on a Server

How to: Insert Data into a Workbook on a Server

Concepts

Accessing Data in Documents on the Server

DiffGrams (ADO.NET)