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Returns the key or index of an item in a collection depending on the value that is passed.
Collection.GetKey(eIndex) |
Parameters
- eIndex
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Specifies a required expression that represents a position of an item in the collection. This expression can be one of two types:
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Numeric. The eIndex expression must have a value from 1 to the value of the Count property of the collection.
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String. The eIndex expression must correspond to the cKey that was specified for the item when it was added to the collection.
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Numeric. The eIndex expression must have a value from 1 to the value of the Count property of the collection.
Return Value
The following table lists the return values for GetKey.
| Return value | Condition |
|---|---|
|
String (key) |
When passing an index or integer value |
|
Integer (index) |
When passing a key or string |
|
Empty string ("") |
When passing an index that does not exist or if items were added to the collection without keys |
|
0 |
When passing a key that does not exist |
Remarks
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Because the GetKey method returns a value, you need to add a RETURN statement to the end of GetKey in the source code for any subclass you have modified. For example:
If you do not want to return the value, use the RETURN command without the DODEFAULT() function.В 
Copy CodeRETURN DODEFAULT( eIndex )
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To determine if keys were specified when items were added to the collection, you can use the statement
GetKey(1)and the EMPTY() function to check for an empty return value as follows:
В Copy Code? !EMPTY(Collection.GetKey(1))
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To derive the index or key from an item in a collection from within a FOR EACH loop, use a normal FOR loop instead of a FOR EACH loop.
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Visual FoxPro generates an error if the wrong type or no parameter is passed to GetKey.
Example
The following example illustrates the following tasks after creating a collection and adding items:
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Check if items have keys.
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Retrieve and display key for the second item.
| В | Copy Code |
|---|---|
CLEAR
LOCAL oItems AS Collection
oItems = NEWOBJECT("Collection")
oItems.Add("Daffodils", "flower2")
oItems.Add("Roses", "flower1", "flower2")
oItems.Add("Daisies", "flower3")
? !EMPTY(oItems.GetKey(1))
? oItems.GetKey(2) | |