Develop Reference

Edit Items in a ListBox

I am creating a program using WinForms so users can input info into textboxes on one form which then are saved into a Listbox on another form. I would like to be able to edit the items saved in the listbox by opening the original form on a button click. Really struggling with it as I can't think of the code and I can't seem to find a solution.
My Code:
private void btnAdd_Click(object sender, EventArgs e)
{
RoomDisplayForm newRoomDisplayForm = new RoomDisplayForm();
newRoomDisplayForm.ShowDialog();
if(newRoomDisplayForm.DialogResult == DialogResult.OK)
{
listBoxRooms.Items.Add(newRoomDisplayForm.value);
}
newRoomDisplayForm.Close();
}
private void btnRemove_Click(object sender, EventArgs e)
{
this.listBoxRooms.Items.RemoveAt(this.listBoxRooms.SelectedIndex);
}
private void btnEdit_Click(object sender, EventArgs e)
{
}
So i've got a Add and Remove button which work perfectly just need a solution to the edit button.
Thanks in advance

I'm guessing newRoomDisplayForm.value is a property or a public member inside the form. You just need to do something like this:
private void btnEdit_Click(object sender, EventArgs e)
{
if(listBoxRooms.SelectedIndex < 0) return;
var tmpValue = listBoxRooms.Items[listBoxRooms.SelectedIndex].ToString();
RoomDisplayForm newRoomDisplayForm = new RoomDisplayForm();
newRoomDisplayForm.value = tmpValue;
newRoomDisplayForm.ShowDialog();
//TODO: inside "newRoomDisplayForm" set the value to the textbox
// ie.: myValueTextBox.Text = this.value;
if(newRoomDisplayForm.DialogResult == DialogResult.OK)
{
// replace the selected item with the new value
listBoxRooms.Items[listBoxRooms.SelectedIndex] = newRoomDisplayForm.value;
}
}
Hope it helps!

You can simply remove the listitem in that specific position, create a new item and add it again. it's kind of replacement.

Winforms - Stop Dropdown of Combobox during DropDown event

I need to implement a ComboBox, which acts as follows:
When Click on the ComboBox, the client calling API method and updates the combobox items with the response.
My problem is, when I have 0 results - I want the ComboBox not to open (It has 0 items).
Is there a way to do that?
This is my current code:L
private void Combo_DropDown(object sender, EventArgs e)
{
// Private method which addes items to the combo, and returns false if no itmes were added
if (!AddItemsToComboBox())
{
// This is not working
Combo.DroppedDown = false;
}
}

You can make the DropDownHeight as small as possible (1). For example:
int iniHeight;
private void Form1_Load(object sender, EventArgs e)
{
iniHeight = Combo.DropDownHeight;
}
private void Combo_DropDown(object sender, EventArgs e)
{
Combo.DropDownHeight = (AddItemsToComboBox() ? iniHeight : 1);
}

how to save comboxitems using project settings in c#

I want to save my ComboBox items so that after closing the window application i restore previous items in ComboBox which i saved. I Declare Combobox item in project setting of type system.collection.specialized.stringcolection. my code for is given below.
private void Form1_Load(object sender, EventArgs e)
{
comboBox1.Items.Add(Properties.Settings.Default.combox);
}
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
ArrayList arraylist = new ArrayList(this.comboBox1.Items);
Properties.Settings.Default.combox = arraylist;
}
but it show error:
Cannot implicitly convert type 'System.Collections.ArrayList' to
'System.Collections.Specialized.StringCollection'

Get your items from settings and check if they're null. If they're not null, add them to your ComboBox.Items collection.
private void Form_Load(object sender, EventArgs e)
{
var comboboxItems = Properties.Settings.Default.ComboboxItems;
if (comboboxItems != null)
comboBox.Items.AddRange(comboboxItems.Cast<string>().ToArray());
}
When form is closing you need to put your items inside StringCollection format if you're willing to save them. So convert items from your ComboBox.Items collection to string array and add them inside StringCollection. Place your fresh collection into Settings.Default and important thing, don't forget to save changes.
private void Form_FormClosing(object sender, FormClosingEventArgs e)
{
var comboboxItems = new StringCollection();
comboboxItems.AddRange(comboBox.Items.Cast<string>().ToArray());
Properties.Settings.Default.ComboboxItems = comboboxItems;
Properties.Settings.Default.Save();
}

Put this in your Form1_FormClosing method:
System.Collections.Specialized.StringCollection items =
new System.Collections.Specialized.StringCollection();
items.AddRange(this.comboBox1.Items.Cast<string>().ToArray());
Properties.Settings.Default.combox = items;

Change datasource on button click in Winforms app

I have a datagridview (dataGridView1) pulling information out of a mdb datasource called rentBindingSource, how can I pull information out of hireBindingSource on a button click i.e.
private void viewHire_Click(object sender, EventArgs e)
{
// refresh datagrid view to load stuff from hireBindingSource
}

Try this:
private void viewHire_Click(object sender, EventArgs e)
{
dataGridView1.DataSource = hireBindingSource;
}

First mouse click event on an item in a listbox doesn't trigger the function

I am trying to do something like: when a user select an item on a listbox, then the function listboxClicked will be triggered. However, the first click often does not able to trigger the function. It only triggers the function when I click the same item or another item for the second time.
May I know what's wrong with my code? Thank you.
My Code:
private void listbox_SelectedIndexChanged(object sender, EventArgs e)
{
listbox.MouseClick += listboxClicked;
}
private void listboxClicked(object sender, EventArgs e)
{
if (listbox.SelectedIndex != -1)
{
//do something
}
}

Try this one:
Listbox1_SelectedValueChanged(object sender, EventArgs e)
{
Listbox listbox = (Listbox)sender;
MessageBox.Show(listbox.SelectedItem.ToString());
}