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How to: Programmatically cache a data source in an Office document

  • Article

Applies to: yesVisual Studio noVisual Studio for Mac

Note

This article applies to Visual Studio 2017. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here

You can programmatically add a data object to the data cache in a document by calling the StartCaching method of a host item, such as a Document, Workbook, or Worksheet. Remove a data object from the data cache by calling the StopCaching method of a host item.

The StartCaching method and the StopCaching method are both private, but they appear in IntelliSense.

Applies to: The information in this topic applies to document-level projects for Excel and Word. For more information, see Features available by Office application and project type.

When you use the StartCaching method to add a data object to the data cache, the data object does not need to be declared with the CachedAttribute attribute. However, the data object must meet certain requirements to be added to the data cache. For more information, see Cache data.

To programmatically cache a data object

  1. Declare the data object at the class level, not inside a method. This example assumes that you are declaring a DataSet named dataSet1 that you want to cache programmatically.

    public DataSet dataSet1;

    Public dataSet1 As DataSet

  2. Instantiate the data object, and then call the StartCaching method of the document or worksheet instance and pass in the name of the data object.

    dataSet1 = new DataSet();

if (!this.IsCached("dataSet1"))
{
    this.StartCaching("dataSet1");
}

    dataSet1 = New DataSet()

If Not (Me.IsCached("dataSet1")) Then
    Me.StartCaching("dataSet1")
End If

To stop caching a data object

  1. Call the StopCaching method of the document or worksheet instance and pass in the name of the data object. This example assumes that you have a DataSet named dataSet1 that you want to stop caching.

    if (this.IsCached("dataSet1"))
{
    this.StopCaching("dataSet1");
}

    If (Me.IsCached("dataSet1")) Then
    Me.StopCaching("dataSet1")
End If

    Note

    Do not call StopCaching from the event handler for the Shutdown event of a document or worksheet. By the time the Shutdown event is raised, it is too late to modify the data cache. For more information about the Shutdown event, see Events in Office Projects.

See also