[Gambas-user] help with ListView code?

[mikeB]

Greetings,

I just want to give a BIG THANK YOU to all those that responded to help

me solve this problem - special gratitude goes out to 'Tobias Boege'

for his time and efforts to give me a better picture of whats going

on with the "ColunmView" control. I've still got a few problems to solve

but at least I now have what I might need to solve them;-)


Without you experienced Gambas coders offering your time and knowledge =

I don't see how any "newbie', to the language, would get much done - 
cuz, while

it's true "Gambas is Almost Basic" there's a lot of difference (as you 
all know).

I will publish the new Gambas GNU app I am writing so that other 
"newbies" might

have a better time of using this control (Learn by Example).


THANKS AGAIN and HAVE A GREAT DAY,

mikeB



On 07/28/2017 07:47 AM, Tobias Boege wrote:
> On Thu, 27 Jul 2017, mikeB wrote:
>> Greetings all,
>> I've got a Listview (set as Column view) with 2 columns that I'm using
>>
>> for testing so I might understand how all this works so can add it to a
>> project.
>>
>> testCode..................................................
>> With listview1
>>      .Clear
>>      .Resizable = True
>>      .Columns.Count = 2
>>      .Columns[0].Text = "Site Name:"
>>      .Columns[1].Text = "Site URL:"
>> End With
>> ..................................................................
>> I can add values to the 1st column:
>> code..........................................................
>> listview1.add("1", "First var entry")
>> listview1.add("2", "Second var entry to test the resize ability")
>> listview1.add("3", "Third var entry")
>> ...................................................................
>> Have spent a lot of research time trying to figure out how to add
>> values to the 2nd column (Site URL:) - got me stumped.
>>
>> Anyone got an example line of code to help me out?
>>
>> I can't seem to find the answer in the help docs.
>>
>> Would greatly appreciate any/ all help;-)
>> mikeB
>>
> You don't really have a ListView but a ColumnView, do you? A ColumnView is
> a ColumnView and not "a Listview (set as Column view)". The ListView control
> doesn't have a Columns property.
>
> I have to say that when I tried to answer your question, I noticed that
> I had no clue how ListView, its sibling ColumnView or their mutual parent
> _TreeView work, so I read their source code (see gb.gui.base) -- and I
> still had no clue. And let me say that this happens rarely to me these days.
> I had to dig up an example (the FileView class in gb.form is very nice)
> to see what they actually do with their columns. Since I get it now, I want
> to give an explanation of these classes first, so bear with me.
>
> To understand ColumnView you have to understand _TreeView, because
> ColumnView is basically a _TreeView with some code added to manage columns,
> but the columns are already available from _TreeView.
>
> To add to the confusion, a _TreeView is internally basically a GridView,
> i.e. a square grid of cells in which you can put strings and pictures,
> but you can't access these cells /that/ freely from a _TreeView. The key
> information is that each _TreeView item is an entire *row* in the GridView.
>
> By calling ColumnView.Add("1", "First var entry") you create a new row
> in the GridView, identified by the key "1", and set the text of the first
> column of that row to "First var entry". The return value of the Add()
> method is a _TreeView_Item object which allows you to set the texts of
> all other columns:
>
>    ColumnView.Add("1", "First var entry")[1] = "second column"
>
> Wrap it in a With or store it in a variable if you want to set many other
> columns:
>
>    Dim hItem As _TreeView_Item
>
>    hItem = ColumnView.Add("1", "First var entry")
>    hItem[1] = "second column"
>    hItem[2] = "third column"
>
> The asymmetric treatment of the first vs. the other columns is most likely
> because you always want to set at least the first column's text, and maybe
> of technical nature as the Add() method has optional parameters which make
> it uglier to add a variable argument list (Param in gb) to Add().
>
> Regards,
> Tobi
>