I am working on a Windows Forms application and I have a combobox named cmbCountry. I am binding this combobox to a list which contains names of countries. Following is the code to populate the combobox.
cmbCountry.DataSource = lstcountry;
Next I want to set selected item as "United States of America". so I added the following code
cmbCountry.SelectedItem="United States of America";
I want to do some code on selection change event of this combobox.
private void cmbCountry_SelectionChangeCommitted(object sender, EventArgs e)
{
\\some code
}
This method is suppose to be call when I set the selected item. But it is not getting called. However when I select "United States of America" from UI part(Design Part) this event getting called. I want to get called this event when I set the selected item.
SelectionChangeCommitted fires when the user manipulates via the UI.
SelectionChangeCommitted is raised only when the user changes the
combo box selection. Do not use SelectedIndexChanged or
SelectedValueChanged to capture user changes, because those events are
also raised when the selection changes programmatically.
http://msdn.microsoft.com/en-us/library/system.windows.forms.combobox.selectionchangecommitted.aspx
Use SelectedIndexChanged or SelectedValueChanged
Change your event to SelectedIndexChanged:
private void cmbCountry_SelectedIndexChanged(object sender, EventArgs e)
{
\\some code
}
And change the event handler (which may be automatically generated):
this.cmbCountry.SelectedIndexChanged += new System.EventHandler(this.lstResults_SelectedIndexChanged);
Related
I am developing a windows forms application and load the list from this code:
private void showList()
{
TeamTableAdapter teamAdapter = new TeamTableAdapter();
lstTeamName.DataSource = teamAdapter.GetTeamsActive();
lstTeamName.DisplayMember = "TeamName";
lstTeamName.ValueMember = "TeamID";
}
I want to enable a button if the user selects one of the items. What event should I put the code into. I the following code but the event seems to fire before the user clicks on the list.
private void lstTeamName_Click(object sender, EventArgs e)
{
if (lstTeamName.SelectedIndex > -1)
btnImportXML.Enabled = true;
}
I moved my code to the SelectedIndexChange event but it still fires before the user selects an item and the selectedIndex is 0.
You dont want to bind to the Click event but to the SelectedIndexChanged event. You should be able to accomplish this by simply double clicking on the Control in designer.
I would agree that you don't want to bind to Click as that will likely fire too early.
I recommend you look into the DropDownStyle property. http://msdn.microsoft.com/en-us/library/system.windows.forms.comboboxstyle(v=vs.110).aspx. If you set that to DropDownList then the SelectedItemChanged will fire and SelectedIndex could be > -1
If you leave it as the default DropDown then you may want to use TextChanged and check the Text property.
I would like to capture the event when user changes value of ComboBox by typing.
The SelectedIndexChanged only works if user chooses an option from drop down value, what about when ComboBox text is changed by typing.
The TextChanged event will work for you
ComboBox1_TextChanged(Object sender, EventArgs e)
I'm having problems with the autocomplete property of a combobox. I want to trigger the SelectionChangeCommited event every time I choose an item using the autocomplete but it's not working. The only way the event is triggered is when I use the mouse click and select an option or when the combobox is focused and I use arrow keys on the keyboard. How do I achieve this behaviour using the autocomplete property?
My combo has these properties set:
AutoCompleteMode = SuggestAppend
AutoCompleteSource = ListItems
FormattingEnabled = True
The items in my combo are set with a datasource.
Any ideas?
Thanks
If you mean that you want it to register a change when you start typing:
Call the SelectionChangeCommited event from the TextChanged event.
If you've never done this, the most basic example I could find was on the .net forums here. Granted, the methods shown there are generalities, but is very simple to understand and apply to your code.
EDIT FIXED (as of most recent comment):
Still tie the events together, but instead of using TextChanged, which would occur ever time you type, use the SelectedIndexChanged, which occurs when you use the mouse to select an auto suggested item.
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
comboBox1_SelectionChangeCommitted(sender, e);
}
you canuse a trick and call comboBox1_SelectionChangeCommitted
in Validated event
when ever text in combobox changes and user leave the combo box it will be fired
private void comboBox1_Validated(object sender, EventArgs e)
{
comboBox1_SelectionChangeCommitted(sender, e);
}
When I am having a value item selected in my WPf DropDown Combo Box then navigating using keys Left and right arrow keys result in firing of selected changed event for each item.
How to overcome this problem
The most easy and suitable way I found to overcome this problem is as follows:
rather than using SelectedIndexChanged event I used on DropDownClosed event and all code that is wriiten earlier inside selected index changed moved to this event under a if condition that checks whether a item is selected or not. Like this.
private void OnCmbOperatorsListDropDownClosed(object sender, EventArgs e)
{
if (cmbOperatorsList.SelectedIndex != -1)
InsertText(cmbOperatorsList.SelectedValue.ToString());
//Do whatever u want with selected item
}
So in this way when i navigate through Arrow keys SelectedIndexChagned event will not fired or since i haven't used that event so it will not create any problem.
As per my knowledge this is not possible straight away. I could have implemented this in a kind of "selection simulated" manner.
Handle arrow keys on combobox dropdown in PreviewKeyDown event by setting e.Handled = true. So that usual navigation based selection wont happen.
Inthese handlers based on Keys, change the Background and Foreground of the previous or next item from the drop down list so that it will look as if its selected and highlighted.
Then perform selection of the item which curently has the "simulated selection background - foreground" when dropdown closes. After dropdown closure, revert the background and foreground style.
But thats just my way of doing it.
You can use the PreviewKeyDown event like
private void combo_PreviewKeyDown(object sender, KeyEventArgs e)
{
if (e.Key.Equals(Key.Left) || (e.Key.Equals(Key.Right)))
{
((ComboBox)sender).SelectionChanged -= combo_SelectionChanged;
}
}
and if u want to attach that event you can add this PreviewMouseDown event.
This is what i tried and may not be a proper method of doing such cases
using mysql I feed combobox2 with selection of combobox1.It works OK. but the problem is the first select seems does not trigger the eventhandler. the second time I do it it will trigger.
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
comboBox1.SelectedValueChanged += new EventHandler(comboBox1_selectedvaluechanged);
}
private void comboBox1_selectedvaluechanged(object sender, EventArgs e)
{
region = comboBox1.SelectedItem.ToString();
values_to_venue();
db.connection.Close();
}
It's because you're not creating your event handler until the SelectedIndex of the combobox changes. This is fired alongside SelectedValue changes. Create the event handler in the load method ensuring it is there when the first SelectedValue changes. If you put it in the Load make sure you clean it up with -= in the unload. Or, you can just create it in the constructor and then you won't need to remove it.
You do want to set the events in your constructor or load method; also, I think the event you want to use is ComboBox.SelectionChangeCommitted because if the user navigates the DropDown list using the up/down arrows on the keypad, SelectedIndexChanged will fire before the selection is committed - is that what you want??????