i'm stuck....
this my code to add items to my listview:
ListViewItem item = new ListViewItem(ProjectDomainName);
item.Tag = relatedProject.ProjectId;
lvwSelectedProjects.Items.Add(item);
when i choose 'View.List' as viewmode, i see all items.
When i choose 'View.Details' (which is the setting that i want) i see.... nothing. Well, nothing, i DO get a vertical scrollbar, but no items. And i can scroll too, but no items....
I also added a column in the listview (didn't change the add items code), but that also didn't work
i must be overlooking something?
This code works for me:
using System;
using System.Windows.Forms;
public class LVTest : Form {
public LVTest() {
ListView lv = new ListView();
lv.Columns.Add("Header", 100);
lv.Columns.Add("Details", 100);
lv.Dock = DockStyle.Fill;
lv.Items.Add(new ListViewItem(new string[] { "Alpha", "Some details" }));
lv.Items.Add(new ListViewItem(new string[] { "Bravo", "More details" }));
lv.View = View.Details;
Controls.Add(lv);
}
}
public static class Program {
[STAThread] public static void Main() {
Application.Run(new LVTest());
}
}
Try this code for yourself in an empty project. Then, focus on adapting it to your application: compare how your program is different from this code, and work on changing it to more closely match mine. It's OK if you lose functionality in your program; just try to get a basic version working. Then, add functionality back bit by bit so you can be sure that the program still works every step of the way.
If you're still stuck, post more code from your project and we might have a better idea of why you're having trouble.
Another possible cause of blank items when listview.View = View.Details, is if you don't add any columns to the listview.
For example:
ListView lv = new ListView();
lv.View = View.Details;
lv.Items.Add("Test");
.. will result in a blank ListView.
Adding a column will correct:
...
lv.View = View.Details;
// Add one auto-sized column, to show Text field of each item.
lv.Columns.Add("YourColumnTitle", -2);
...
Because, you should be using a ListViewDataItem instead of a ListViewItem, observe ...
for (int i = 0; i < AudioCdWriter.FileCount; ++i) {
var item = new ListViewDataItem(i.ToString());
item.SubItems.Add(AudioCdWriter.TrackLength((short)i).ToString());
item.SubItems.Add(AudioCdWriter.file[(short)i]);
lvwAudioFiles.Items.Add(item);
}
This happened to me as well (listview not showing items in details view) I just put the following into the code (previously was only in the design) after adding items to the listview and it started showing the items.
lv.View = View.Details;
ListViewItem item = new ListViewItem("item1");
item.SubItems.Add("subitem"); //add subitem if applicable
listview1.Items.Add(item);
this Result can be sold your problem
Related
I am able to get this result successfully from the sample code here
C# .net Windows Forms Listview with image in Detail View using .NET Framework however the same code and form setup using.NET6.0
does not work i.e. the image does not show in the listview. I tried many many suggestions until I realized that the .NET was causing my issues.
Am I missing something for .NET to show the images in the listview?
public partial class Form1 : Form
{
List<string> _list = new();
ImageList serviceLogoList = new ImageList
{
ImageSize = new Size(32, 32),
ColorDepth = ColorDepth.Depth32Bit
};
public Form1()
{
InitializeComponent();
initializeListView();
DirectoryInfo dir = new DirectoryInfo(#"\resources"); //change and get your folder
foreach (FileInfo file in dir.GetFiles())
{
try
{
this.serviceLogoList.Images.Add(Image.FromFile(file.FullName));
}
catch
{
//log error
}
}
foreach (var str in _list)
{
ListViewItem item = new ListViewItem();
item.Text = str;
item.SubItems.Add("OK");
item.ImageIndex = 0; //tried 1,2,3,4,5 as well
listView1.Items.Add(item);
}
}
private void initializeListView()
{
_list.Add("Test1");
_list.Add("Test2");
_list.Add("Test3");
listView1.View = View.Details;
//listView1.LargeImageList = serviceLogoList;
listView1.SmallImageList = serviceLogoList;
listView1.Columns.Add("Name", 100);
listView1.Columns.Add("Status", 100);
}
}
Here is the code as requested. This code works when .NET Framework 4.7.2 is selected instead of .NET 6.0 (LTS). This code is courtesy of a post on StackOverflow but I can't find the link at the moment. The code works based on "Windows Forms App (.NET Framework)" but not on "Windows Form App"
Add a listview control to the form called listView1. Everything else is done in the code behind.
An update on this. It seems the control I was using which was from the MaterialSkin (link takes you to an issue raised by someone else) package does not support images. I changed out the control for a Winform one and everything works as intended. I created a blank form, added one listview control named listview1, and changed the view type to details. I will style the control to match the rest of my UI.
public Form1()
{
InitializeComponent();
ImageList imageListSmall = new ImageList();
imageListSmall.Images.Add(Bitmap.FromFile("D:\\subtract.png"));
imageListSmall.Images.Add(Bitmap.FromFile("D:\\add.png"));
listView1.SmallImageList = imageListSmall;
listView1.Columns.Add("Item Column", -2, HorizontalAlignment.Left);
listView1.Items.Clear();
ListViewItem item1 = new ListViewItem("item1", 0);
listView1.Items.Add(item1);
item1 = new ListViewItem("item2", 1);
listView1.Items.Add(item1);
}
So, I have two options:
aComboBox.Item.AddRange(stringArray);
aComboBox.SelectedItem = stringFromStringArray;
and
aComboBox.DataSource = stringArray;
aComboBox.SelectedItem = stringFromStringArray;
Now, the first one is waaaaay slower when it comes to initialization (about 5-6 times). It does set the selected item properly, but still, it's very slow so I decided to go with the second one.
But, if I use the second one, the Items array within the aComboBox is not yet set when the second command is executed, so the selected item is the one at index 1, instead the one specified.
The question is, how do I get the performance of the second one with the functionality of the first one?
EDIT:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace ComboBoxTest
{
class MainWindow : Form
{
string[] list = new string[1548];
TableLayoutPanel panel = new TableLayoutPanel();
public MainWindow() : base()
{
Height = 2000;
Width = 1000;
Random rand = new Random();
for (int i = 0; i < 1547; i++)
{
list[i] = rand.Next().ToString();
}
list[1547] = 5.ToString();
Button button = new Button();
button.Text = "Press me";
button.Click += Button_Click;
panel.Controls.Add(button, 0, 0);
panel.Height = 2000;
panel.Width = 1000;
Controls.Add(panel);
Show();
}
private void Button_Click(object sender, EventArgs e)
{
for (int i = 0; i < 36; i++)
{
ComboBox box = new ComboBox();
box.DataSource = list; //box.Items.AddRange(list);
box.SelectedItem = 5.ToString();
panel.Controls.Add(box, 0, i+1);
}
}
}
}
I reproduced the problem with this program. If you change it to addRange(), it will take a lot more time, but it will set the item.
Try adding a breakpoint to the SelectedItem and then look at the ComboBox.
If you set the one, the other will be null (DataSource vs. Items). The ComboBox seems to look into Items to check if the string exists within the list, and that's why it fails with DataSource method.
Bonus question: Why are all ComboBoxes working as one (try changing the value)?
The question is, how do I get the performance of the second one with
the functionality of the first one?
If you want it to work properly, you can move the line box.SelectedItem = 5.ToString(); to the line after adding boxes to panel.
When you use DataSource for your combo box, setting SelectedItem works only if your combo box exists on your form.
I'm not sure about performance, but sure about functionality.
Bonus question: Why are all ComboBoxes working as one (try changing
the value)?
Because they are bound to the same DataSource. In fact they are using a single BindingManagerBase.
You can use different BindingSource for them. Also you can bind them to list.ToList().
Use teh DataSource method and use the FindString method to find the index of your desired selected text:
string[] arrString = {"hello", "how r u", "fine" };
comboBox1.DataSource = arrString;
comboBox1.SelectedIndex=comboBox1.FindString("fine");
MessageBox.Show(comboBox1.SelectedIndex.ToString());
I'm gonna' cut right to the chase here, and confess that I'm a bit of a newb at this stuff, so bear with me.
I have a list of myObjects. Each myObject has a few variables.
What I want to do is to be able to insert said object's variables into a ListView, and then be able to search through said variables with a basic TextBox. The results of this search will be the only entries in my ListView as the user types.
I fill my ListView like this:
ListView lv = new ListView();
lv.Columns.Add("FirstVariable");
lv.Columns.Add("SecondVariable");
lv.Columns.Add("ThirdVariable");
lv.View = View.Details;
lv.Width = 500;
lv.Height = 500;
foreach (var value in myListOfObjects)
{
lv.Items.Add(new ListViewItem(new string[] { value.key, value.title, value.typeName }));
}
//...
Now, I also have a TextBox in my Form, which I hope can be used to search through the rows of information in my ListView as the user types.
How would I go about doing this?
Can I use EventHandler on my TextBox to perhaps repopulate the ListView on each keypress or something?
If so, could anyone demonstrate how to do so?
What you need to do is;
On textbox_textChanged - remove all items from the listview and then add the ones that match an example could be;
Warning - Sudo code incoming!
textbox_textChanged(Sender sender, SomeArgs args)
{
lv.Clear();
foreach(var item in originalCollection)
{
if(item.name.Contains(textbox.Text)
lv.Add(item);
}
}
The ListView seems to be as cantankerous as a polecat and as temperamental as a [elided by the P.C. police]
With help from - and others, I was able to get a ListView working just as I wanted
it to
(http://stackoverflow.com/questions/11423537/how-to-add-subitems-to-a-listview).
Now I'm converting that simple demo for use in a real app.
I create the columns in the form's Load event:
listViewGroupsItems.Columns.Add(colHeadName);
listViewGroupsItems.Columns.Add(colHeadRate);
...but they don't display. However, there is a blank line above my first item. So why are no text values being displayed. Are they "there" but invisible? Why would they get wiped out?
Anyway, what I want to see is:
column1Title column2Title
Group1Name
Item subitem
Item subitem
Group2Name
Item subitem
Group1Name
Item subitem
Item subitem
Item subitem
Item subitem
...but what I actually see is just:
[blank line]
Group1Name
...that's it!
The ListView's View property is set to Details; otherwise, all of the properties are the default values.
My listview code is:
private void AddGroupsAndItems() {
Dictionary<string, string> GroupsDict = PlatypusData.GetGroupsForTopLevel(Convert.ToInt32(labelTopLevel.Tag));
int currentGroup = 0;
foreach (KeyValuePair<string, string> entry in GroupsDict) {
string GroupNumber = entry.Key;
string GroupName = entry.Value;
listViewGroupsItems.Groups.Add(new ListViewGroup(GroupName, HorizontalAlignment.Left));
Dictionary<string, string> ItemsDict = PlatypusData.GetItemsForGroup(GroupNumber);
foreach (KeyValuePair<string, string> itemEntry in ItemsDict) {
string itemID = itemEntry.Key;
string itemName = itemEntry.Value;
ListViewItem lvi = new ListViewItem(string.Format("{0} ({1})", itemName, itemID));
lvi.SubItems.Add(PlatypusData.GetDuckbillNameForItemId(itemID));
listViewGroupsItems.Items.Add(lvi);
listViewGroupsItems.Groups[currentGroup].Items.Add(lvi);
}
currentGroup++;
}
}
UPDATE
I changed my code in the form's Load event from:
var colHeadName = new ColumnHeader { Text = Resources.RateRequestForm_RateRequestForm_Load_Billing_Account_Client, Width = 160 };
var colHeadRate = new ColumnHeader { Text = Resources.RateRequestForm_RateRequestForm_Load_RatePlan_ID, Width = 120 };
listViewCustomerBillAccountsClients.Columns.Add(colheadName); //colHeadName);
listViewCustomerBillAccountsClients.Columns.Add(colheadRate); //colHeadRate);
...to:
ColumnHeader colheadName = new ColumnHeader();
ColumnHeader colheadRate = new ColumnHeader();
listViewCustomerBillAccountsClients.Columns.Add(colheadName);
listViewCustomerBillAccountsClients.Columns.Add(colheadRate);
...and it made no difference at all.
It would seem that the ColumnHeader constructor should be able to take a string of what it should display, but even when I do that:
ColumnHeader colheadName = new ColumnHeader("This");
ColumnHeader colheadRate = new ColumnHeader("That");
...there is still no change (according to Intellisense or whatever it's called, the string arg is an ImageKey, but I thought I'd try just out of thoroughness/frustration.
Late to the party, but I've just spent some time trying to solve a similar problem. The answer I found was that when clearing the list before filling, you must use
listviewGroupItems.Items.Clear();
not
listviewGroupItems.Clear();
The ListView.Clear() method clears everything from the control--including the columns
I had the same issue today. I had coded listView.Clear() as user2867342 mentioned. I needed to change that to listView.Items.Clear(), but that did not make the columns appear. The columns were there, and I could click on them and resize them, but they were completely blank.
I had a ListView set to Details mode. I also had set the OwnerDraw property to true, because I wanted to paint my own progress bar column. MSDN says the following about the OwnerDraw property (emphasis mine):
A ListView control is normally drawn by the operating system. In order
to customize the appearance of ListView items, subitems, and column
headers, set the OwnerDraw property to true and provide a handler for
one or more of the following events: DrawItem, DrawSubItem,
DrawColumnHeader. This is called owner drawing. When the View property
is set to View.Details, all three events occur; otherwise, only the
DrawItem event occurs.
I had to implement the DrawColumnHeader event. In my case, the defualt worked fine, so the method sets the DrawDefault event parameter to true. After implementing this event handler, the column headers appeared correctly:
...Windows.Forms designer code...
listView.DrawColumnHeader += new DrawListViewColumnHeaderEventHandler(this.listView_DrawColumnHeader);
...
private void listView_DrawColumnHeader(object sender, DrawListViewColumnHeaderEventArgs e)
{
e.DrawDefault = true;
}
You're missing column headers in your code. (fixed)
Per the MSDN:
"If your ListView control does not have any column headers specified and you set the View property to View.Details, the ListView control will not display any items. If your ListView control does not have any column headers specified and you set the View property to View.Tile, the ListView control will not display any subitems."
Granted, you'll probably need to make more adjustments than what you see in my SS, but it at least answers your question as to why you are getting blanks.
Edit (Changed lines, although changing them back to your code didn't skew my successful results):
lvi.Group = listViewGroupsItems.Groups[currentGroup];
listViewGroupsItems.Items.Add(lvi);
One more thing to check I just found:
OwnerDraw must be false.
Copy & Paste from previous project and forgot that I used OwnerDraw
We have a custom collection of objects that we bind to a listbox control. When an item is added to the list the item appears in the listbox, however when one selects the item the currency manager position will not go to the position. Instead the currency manager position stays at the existing position. The listbox item is high lighted as long as the mouse is press however the cm never changes position.
If I copy one of the collection objects the listbox operates properly.
One additional note the collection also has collections within it, not sure if this would be an issue.
I found the issue, after spending way too much time....
This issue was related to one of the propertys of the item(custom class) in the collection which was bound to a date picker control. The constructor for the class never set the value to a default value.
This caused an issue with the currency manager not allowing the position to change as the specific property (bound to the date picker) was not valid.
Me bad! I know better!
You might need to post some code; the following (with two lists tied together only by the CM) shows that it works fine... so to find the bug we might need some code.
using System;
using System.ComponentModel;
using System.Windows.Forms;
static class Program
{
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
BindingList<Foo> foos = new BindingList<Foo>();
foos.Add(new Foo("abc"));
foos.Add(new Foo("def"));
ListBox lb1 = new ListBox(), lb2 = new ListBox();
lb1.DataSource = lb2.DataSource = foos;
lb1.DisplayMember = lb2.DisplayMember = "Bar";
lb1.Dock = DockStyle.Left;
lb2.Dock = DockStyle.Right;
Button b = new Button();
b.Text = "Add";
b.Dock = DockStyle.Top;
b.Click += delegate
{
foos.Add(new Foo("new item"));
};
Form form = new Form();
form.Controls.Add(lb1);
form.Controls.Add(lb2);
form.Controls.Add(b);
Application.Run(form);
}
}
class Foo
{
public Foo(string bar) {this.Bar = bar;}
private string bar;
public string Bar {
get {return bar;}
set {bar = value;}
}
}
Collections don't have a sense of "current item". Perhaps your custom collection does, but the ListBox is not using that. It has its own "current item" index into the collection. You need to handle SelectedIndexChanged events to keep them in sync.