Skip to content

The tWebNavigateData Struct

Understanding Navigation
The Forward Navigation Process

The tWebNavigateData struct is used to pass information forward or back from one view to another in the view stack. When you navigate forward, most of this data is initialized for you by the framework. The framework uses this to define standard navigation initializations and behaviors for the view being displayed. It is also used by the developer to handle customizations. The newly displayed view stores this data in a private web property. This data can be accessed using GetNavigateData and SetNavigateData. During a navigate back operation, the data is passed back to the invoking view so it can be used to update any changes.

Definition

The tWebNavigateData struct is defined as follows:

Struct tWebNavigateData
    Integer eNavigateType
    Integer iTable
    Integer iColumn
    String sRowID
    Boolean bNewRecord
    Boolean bReadOnly
    Boolean bSaveBeforeNavigate
    tNameValuePair[] NamedValues
End_Struct

Members

  • eNavigateType
    This contains the navigate-from type. When NavigateForward is sent, this type is determined for you and is then moved to this member. Valid values are nfFromMain, nfFromChild, nfFromParent, and nfUndefined.

  • iTable
    This is the table number associated with the invoking object that started the navigate forward process. If the value is non-zero, it is expected that there will be a DDO in the view for this table. If the invoking object is data bindable (i.e., if it supports the Entry_Item syntax), this table value will be used here. If it is not data bindable, the Main_File value of the invoking view’s DDO Server is used. This is usually maintained by the framework.

  • iColumn
    This is the table column number associated with the invoking object that started the navigate forward process. If the invoking object is data bindable (i.e., if it supports the Entry_Item syntax), this bound column value will be used here. If it is not data bindable, it will be 0. This is usually maintained by the framework.

  • sRowID
    During forward navigation, this is set to a serialized version of the RowID associated with iTable. During back navigation, this will be set to the RowID of the view being closed. This is usually maintained by the framework.

  • bNewRecord
    During forward navigation, the developer can set this to True to indicate that the view being navigated to will be cleared for new data entry. Normally, this would be set in OnGetNavigateForwardData when moving from a Select view to a Zoom view.

  • bReadOnly
    During forward navigation, the developer can set this to True to indicate that the view being navigated should be read-only. Normally, this would be set in OnGetNavigateForwardData when moving from a Select view to a Zoom view.

  • bSaveBeforeNavigate
    This allows you to specify that the data in the invoking view must be saved before a forward navigation. When set to True, a save will be attempted before the navigation. If this save fails or there was nothing to save (an empty record), the navigation is canceled. Normally, this would be set in OnGetNavigateForwardData when moving from a Zoom view to a child Select or Zoom view.

  • NamedValues
    This is an array of name/value pairs. This can be used by the developer to pass additional data back and forth between the invoking view and the invoked view. The values and meanings of these named data pairs must be defined by the developer. They have no meaning and are not used by the framework. These would be set in OnGetNavigateForwardData and OnGetNavigateBackData. If set, you will need to write code to get these data values and act on them. This is often done in the OnNavigateForward and OnNavigateBack events. Methods exist in the cWebView class that allow you to add named value pairs to this array (NamedValueAdd) and to find a value based on its name (NamedValueGet and NamedValueIndex).

See Also