вЂNothingвЂ™) for the index would result in no image, but thatвЂ™s not the case. In this case, thatвЂ™s the Information icon. Also, youвЂ™ll see that the Root Node (the one that has вЂSystem Icons DemoвЂ™ as its text) shows the image that has the index value of 0. Note that the image will revert to the default one as soon as a new node is selected. Will be displayed when a node is selected. You can see that the image thatвЂ™s designated by the second index value in the Node constructor To take two examples of what happens when a node is selected: The final node uses the fourth image in the ImageList (its index is set to 3, and the list is zero based). In this example, that image is the SystemвЂ™s Information icon. That means that those nodes will display the first item in the TreeViewвЂ™s ImageList by default. If you look at the index values, youвЂ™ll see that with the exception of the final node, the first index is set to 0. So letвЂ™s see the result when the application first runs: Again, IвЂ™ve constrained their size, although it isnвЂ™t really necessary to do this twice.ДЇinally in this snippet the MyImages ImageList is assigned to the ImageList property of the TreeView.ДЄt this stage, those index values I used when creating the nodes earlier will now point to images that do actually exist. In this example IвЂ™ve used four of the icons that ship with Windows.

Then, you can add some images to the ImageList. This will constrain the size of all images and вЂ“ assuming youвЂ™ve picked suitable original images вЂ“ will make the finished icons look better. Once created, you can set various properties, including the ImageSize property as shown above. ' Create a new ImageList Dim MyImages As New ImageList() You can do this by dragging one from the Toolbox and setting its properties in the Properties pane. The next step is to create an ImageList control. An index that points to the image to be shown when this node is the selected node.ДЄt the moment, the values of the two indexes wonвЂ™t actually cause images to display because I havenвЂ™t yet created the required image list.An index that points to the image to be shown by default with this node.The four child nodes that are created next each have : There are other overloads of this constructor that will let you add further detail but IвЂ™m omitting those for simplicity. ' Optionally ensure all are visible at the startДЇirst, it creates a new node and gives it some text to display. ' Add this node and its children to the TreeView ( 'Change 1', 'Info to Exclamation', 0, 1) ( 'No change', 'No change when selected', 0, 0) Then ExpandAll() method is called on TreeView instance to get all nodes visible, since we are going to take a snapshot on the last line, all nodes better be visible. ' Create Node Dim Node1 As TreeNode = New TreeNode( 'System Icons Demo') The test first creates a WinForms TreeView control and calls the LoadJsonToTreeView() method (System Under Test) with a simple JSON string.

Winforms treeview