object from treeview help needed
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Within a loop, I am creating an unknown number of objects. The object has 3 properties. This object has a ToString override. Directly after that object is created, it is added to a list and added as a node, and the ToString override is the visible node text. So what is actually stored in the treeview (text or the object) and how do I retrieve the object/get at it's properties when the node is selected? Thank you.
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Within a loop, I am creating an unknown number of objects. The object has 3 properties. This object has a ToString override. Directly after that object is created, it is added to a list and added as a node, and the ToString override is the visible node text. So what is actually stored in the treeview (text or the object) and how do I retrieve the object/get at it's properties when the node is selected? Thank you.
What is in the TreeView is whatever you added to it, from the sound of it, instances of your little class. Those instances get stored in the Nodes collection, on which you can operate with a set of methods, and which you can index like an array. :)
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages
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What is in the TreeView is whatever you added to it, from the sound of it, instances of your little class. Those instances get stored in the Nodes collection, on which you can operate with a set of methods, and which you can index like an array. :)
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages
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Thank you. df is the name of the object created in the loop. when using: myNode = new TreeNode(); How do I add the object? Currently I think I'm only adding a string by using: myNode = new TreeNode(df.ToString()); Your comments are appreciated.
as you seem to add just strings, all you've got in the tree is strings. drop the ToString() and the tree will look the same but hold real objects now. I think you should be able to figure that out yourself. BTW: the same would apply to other list oriented controls such as ComboBox, ListBox, ... :)
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages
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as you seem to add just strings, all you've got in the tree is strings. drop the ToString() and the tree will look the same but hold real objects now. I think you should be able to figure that out yourself. BTW: the same would apply to other list oriented controls such as ComboBox, ListBox, ... :)
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages
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I thought I could, but when using the object as the argument, I get an error myNode = new TreeNode(df); "Argument '1' cannot convert '...DetailFob' to 'String' " Sorry if this is so simple. I did try this before posting.
Hi, sorry I was wrong (I use ListBox a lot, and TreeView very rarely). In ComboBox and ListBox, you can add arbitrary types as items to the list, and what you see is its ToString result (unless OwnerDraw is in effect); however in a TreeView the items have to be TreeNode instances (the tree needs a standard way to find its branches and leaves, a ComboBox/ListBox doesn't have any hierarchy) and what you see is the TreeNode.Text I see basically two ways to store more than just a string in a TreeView node: 1. create a TreeNode as you did, and store a reference to your object in the TreeNode.Tag property, which is there for you to use any way you like; you still have to provide a Text to the TreeNode (which you did), and if you want Find() to be successful, you should also set the Name property to the text value. 2. create a new class, say MyTreeNode, inheriting from TreeNode. You still need to explicitly set the Text property (as well as Name for a successful Find), but you no longer need to use Tag. As we don't have multiple inheritance nowadays, if you wanted to store say a Form in a tree (Form inherits from Control), you would have to use the first way (with Tag). The main difference between both methods is the Tag indirection: the first item would be myTree.Nodes[0].Tag in (1) and myTree.Nodes[0] itself in (2) :)
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages
-
Hi, sorry I was wrong (I use ListBox a lot, and TreeView very rarely). In ComboBox and ListBox, you can add arbitrary types as items to the list, and what you see is its ToString result (unless OwnerDraw is in effect); however in a TreeView the items have to be TreeNode instances (the tree needs a standard way to find its branches and leaves, a ComboBox/ListBox doesn't have any hierarchy) and what you see is the TreeNode.Text I see basically two ways to store more than just a string in a TreeView node: 1. create a TreeNode as you did, and store a reference to your object in the TreeNode.Tag property, which is there for you to use any way you like; you still have to provide a Text to the TreeNode (which you did), and if you want Find() to be successful, you should also set the Name property to the text value. 2. create a new class, say MyTreeNode, inheriting from TreeNode. You still need to explicitly set the Text property (as well as Name for a successful Find), but you no longer need to use Tag. As we don't have multiple inheritance nowadays, if you wanted to store say a Form in a tree (Form inherits from Control), you would have to use the first way (with Tag). The main difference between both methods is the Tag indirection: the first item would be myTree.Nodes[0].Tag in (1) and myTree.Nodes[0] itself in (2) :)
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages
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you're welcome. :)
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages
-
Within a loop, I am creating an unknown number of objects. The object has 3 properties. This object has a ToString override. Directly after that object is created, it is added to a list and added as a node, and the ToString override is the visible node text. So what is actually stored in the treeview (text or the object) and how do I retrieve the object/get at it's properties when the node is selected? Thank you.
Store the selected node into Treenode. After that you can get all properties of node through object of treenode.