Interactive Documents > The Tab-Index

Using the Tab key, the focus is switched from one control to another along the Tab-Index.

Each control in a VPE Document has assigned a unique Tab-Index, which is an integer value. The Tab-Index determines the order in which the user can Tab through the controls: if the user presses the Tab key on the keyboard, VPE will search the whole document for the control with the next higher Tab-Index and set the focus on it. The reverse is done, if the user presses Shift + Tab ("Backtab").

If you are using templates, the Tab-Index can be assigned to each object using dycodoc (in the object's properties dialog). If you are creating the controls by code (e.g. by calling VpeFormFieldControl(), VpeCheckbox(), etc.), VPE assigns automatically a Tab-Index to each object in the order of creation.

VPE offers to read and also to change the Tab-Index property of each object by code, so your application can modify the Tab-Order of a document at runtime. But special care must be taken: make sure that you don't assign one and the same Tab-Index to more than one object. The Tab-Index must be unique.