Chapter 5Chapter 5: ChildObjectsOverviewWe looked at the ChildObjects method earlier in the Descriptive Programming chapter. This chapter discusses ChildObjects in detail and highlights the key concepts that users should be aware of.Let's look again at how we use ChildObjects.

Dim oDescSet oDesc = Description.CreateoDesc("micclass").value = "WebEdit"oDesc("name").value = "txt_.*"

'Find all the childObjectsSet allTextBox = Browser("B").Page("P").ChildObjects(oDesc)

Dim iFor i = 0 to allTextBox.Count - 1

'Clear the textbox allTextBox(i).Set ""Next

One thing we need to understand is that allTextBox is a collection of objects which is mapped to the runtime objects present at that moment in the application. If the state of the application changes, the collection will become invalid. The objects derived from ChildObjects are directly mapped to its runtime object and have no associated properties.Consider an object collection of WebEdit objects that was created dynamically at runtime using the following HTML:

TOPROPERTIES OF A RUNTIME COLLECTION OBJECT

Figure 5.1: Demo web page The following code can be used to create the collection:

Dim desc, parent, colEditsSet desc = Description.Createdesc("micclass").Value = "WebEdit"Set parent = Browser("name:=TOProperties.*").Page("micclass:=Page")Set colEdits = parent.ChildObjects(desc)

Visually speaking, we know that the colEdits collection must contain five objects of type (micclass) WebEdit. A loop can be used to retrieve properties of each object using GetROProperty. However, what will the code return if GetTOProperty were to be used instead? Below is a demonstration of values retrieved using GetROProperty vs GetTOProperty:

For ix = 0 To colEdits.Count - 1 Print "Object_Index " & ix & "->" & colEdits(ix).GetROProperty("name")Next

Figure 5.2: Print results Considering the output above, a user might expect the same values when using GetTOProperty. However, this is not the case. Consider the same loop using GetTOProperty:

For ix = 0 To colEdits.Count - 1 Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("name")Next

Figure 5.3: Print results Notice that the value of each property returned by the Print statement is Null.The reason behind this behavior is quite simple. The property we have tried to retrieve is a property of a runtime object, not a design-time object. An object returned using the ChildObjects method (DispTOCollection) is always a runtime collection, thus any object present in the collection will only have runtime attributes. This holds true for all properties except micclass. The code below demonstrates that no other property for the target object will be retrieved except for the object's micclass:

For ix = 0 To colEdits.Count - 1 Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("micclass") Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("htmltag") Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("value") Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("outerhtml") Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("abs_x") Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("abs_y") Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("class") Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("disabled") Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("name") Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("readonly") Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("type") Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("x") Print "Object_Index " & ix & "->" & colEdits(ix).GetTOProperty("y") Print vbNewLineNext

Below is the output from the Print statement for the first object in the collection:

Figure 5.4: Print results Tele In summary, for any runtime ChildObjects collection, GetTOProperty will only return the associated value for the micclass property. For all other properties, GetROProperty must be used.If we needed to check for all links on a webpage, the code we would use would be as follows:

Dim oDescSet oDescLink = Description.CreateoDescLink("micclass").value = "Link"oDescLink("html tag").value = "A"

'Find all the childObjectsSet allLinks = Browser("B").Page("P").ChildObjects(oDescLink)

Dim iFor i = 0 to allLinks.Count - 1 'Clear the textbox allLinks(i).Click Browser("B").Back Browser("B").syncNext

When we run the above code, QTP will throw a general run error while it is still in the loop.

Figure 5.5: General run error for ChildObjects loop This happens because when we click the link and return Telecommuni to the previous page, the existing collection is no longer valid. Using an invalid runtime object reference causes the general run error. A workaround to the problem is to regenerate the collection every time inside the loop:

'Find all the childObjectsSet allLinks = Browser("B").Page("P").ChildObjects(oDescLink)

Dim iFor i = 0 to allLinks.Count - 1 Set allLinks = Browser("B").Page("P").ChildObjects(oDescLink)

'Clear the textbox allLinks(i).Click Browser("B").Back

Browser("B").syncNext

This approach will work but has a few constraints. When we click on a link and return to the previous page, the page remains the same in terms of the number of links and their position, but this approach may not always work. If we have a link on the main page which changes the language of the application by setting a cookie, clicking the link and using the back button will cause the main page to have changed completely. Now regenerating the collection inside the loop can create unexpected results. Objects derived from the ChildObjects method differ from the usual ChildObjects in many ways. We will discuss the difference one by oneUsing Init or RefreshObject on Derived ObjectsWhen we use Init or RefreshObject on an object derived from ChildObjects, it basically destroys the object. As we mentioned earlier, objects derived from the Press ChildObjects method have a direct-mapping to the runtime object. When we use RefreshObject on such an object, that mapping is destroyed. Since the derived objects don't have any description of their own, they cannot function. Consider the following example: tions

Set oDescSearch = Description.CreateoDescSearch("micclass").value = "WebEdit"oDescSearch("name").value = "q"

Set oSearchText = Browser("B").Page("P").ChildObjects(oDescSearch).item(0)oSearchText.RefreshObjectoSearchText.Set UCase(Text)

Running the above code raises the following Post error:

Figure 5.6: Object Not found error for referenced object For this reason, we should make sure that we never call RefreshObject on an object that is derived from ChildObjects.

Derived Objects don't Support RegisterUserFuncUntil QTP 11 there was a limitation that impeded using registered methods on derived objects. Consider the following code sample:

Function NewSetMethod(obj, Text) obj.Set UCase(Text)End FunctionRegisterUserFunc "WebEdit", "NewSet", "NewSetMethod"

Set oDescSearch = Description.CreateoDescSearch("micclass").value = "WebEdit"oDescSearch("name").value = "q"

Set oSearchEdit = Browser("B").Page("P").ChildObjects(oDescSearch).item(0)oSearchEdit.NewSet "tarun lalwani"

The above code will throw an error message saying the object doesn't support the property or method

Derived Objects don't Support Objects in Further HierarchyUntil QTP 11 there was a limitation C that impeded using further object hierarchy on derived objects. Consider the following inese code sample:

Set oDescSearch = Description.CreateoDescSearch("micclass").value = "WebTable"

Set oSearchTable = Browser("B").Page("P").ChildObjects(oDescSearch).item(0)oSearchTable.WebEdit("name:=q").Set "tarun lalwani"

The above code will similarly throw an error message saying that the object doesn't support the property or method. Note The workaround to fix this issue is to create a new description and use ChildObjects again on the derived objects.

ChildObject Returns Zero Objects for WebElementsConsider the HTML source below:

test

And the following ChildObjects code:

Dim oDescSet oDesc = Description.Create

oDesc("html tag").value = "DIV"Set allObjects = Browser("Browser").Page("Page").ChildObjects(oDesc)

'Expected Count is 2 but we will get 0MsgBox allObjects.Count

The above code will return the count as 0 because we have not specified the WebElement tag. This is not For true for all tags as TD and TR tags will work without specifying micclass. To fix the issue, just update the code as follow:

Dim oDescSet oDesc = description.CreateoDesc("html tag").value = "DIV"oDesc("micclass").value = "WebElement"Set allObjects = browser("Browser").Page("Page").ChildObjects(oDesc)

'Displays count 2 as expectedMsgBox allObjects.Count

Note Using a wrong case for micclass and generic Web type (WebElement) will produce an incorrect result. oDesc("micclass").value = "webElement" will also return 0. The right case is "WebElement".

Detecting If an Object has been Derived Mmunicatio using ChildObjectsThere is no direct method available for one to detect Teleco if an object has been derived from using ChildObjects, but we can use our understanding of how the derived objects differ from normal objects. The method, however, is not and foolproof.

Function IsDerivedObject(Obj) IsDerivedObject = False If Obj.GetTOProperties().Count = 0 Then 'This is surely a derived object, otherwise we cannot have count as 0 IsDerivedObject = True ElseIf Obj.GetTOProperties().Count = 1 Then 'Now if we only have a micclass property then let's assume 'that it is derived. Though that may not be true. 'Like in case of Browser("micclass:=Browser") If Obj.GetTOProperties().Item(0).name = "micclass" then IsDerivedObject = True End if End ifEnd Function