Initialising button before attempting to enable or disable it (#177)

* Initialising button before attempting to enable or disable it

* Updating class reference

* Adding exception use case

* Removing unused use case

* Including Exception class for classes where exception is used.

src/GridFieldAddNewInlineButton.php

@@ -13,6 +13,7 @@ use SilverStripe\ORM\DataObjectInterface;
 use SilverStripe\ORM\ManyManyList;
 use SilverStripe\View\ArrayData;
 use SilverStripe\View\Requirements;
+use Exception;
 
 /**
  * Builds on the {@link GridFieldEditableColumns} component to allow creating new records.

src/GridFieldAddNewMultiClass.php

@@ -13,6 +13,7 @@ use SilverStripe\Forms\GridField\GridField_HTMLProvider;
 use SilverStripe\Forms\GridField\GridField_URLHandler;
 use SilverStripe\View\ArrayData;
 use ReflectionClass;
+use Exception;
 
 /**
  * A component which lets the user select from a list of classes to create a new record form.

src/GridFieldEditableColumns.php

@@ -17,6 +17,7 @@ use SilverStripe\Forms\LiteralField;
 use SilverStripe\Forms\ReadonlyField;
 use SilverStripe\ORM\DataObjectInterface;
 use SilverStripe\ORM\ManyManyList;
+use Exception;
 
 /**
  * Allows inline editing of grid field records without having to load a separate

src/GridFieldOrderableRows.php

@@ -20,6 +20,7 @@ use SilverStripe\ORM\ManyManyList;
 use SilverStripe\ORM\SS_List;
 use SilverStripe\ORM\SS_Map;
 use SilverStripe\View\ViewableData;
+use Exception;
 
 /**
  * Allows grid field rows to be re-ordered via drag and drop. Both normal data