I have a specific problem with a combobox in visual studio.
I use it to let the user type text in the textbox part of the combobox which immediately starts a SQL requst.
The result should be displayed in the dropdownlist part of the combobox.
(DropDownStyle is set to DropDown)
private void UpdateParent(object sender, EventArgs e)
{
ParentListChange(); //Update the listitems
//prevent from opening at the beginning
if (!ParentSelect.Text.Trim().Equals(""))
{
//my problem
ParentSelect.DroppedDown = true;
Cursor.Current = Cursors.Default;
}
}
But as soon as the drop down opens the first item gets selected and the whole text of it will paste into the textbox.
So if you start to write more then one letter in a row the first one "disappears" because the second typed letter replaces the selected text.
I know there is a similar post but the answeres did not help since they would be to slow (user would have to wait for about a second to type on):
private void comboBox1_TextUpdate(object sender, EventArgs e)
{
var savedText = comboBox1.Text;
comboBox1.DroppedDown = true;
comboBox1.Text = savedText;
comboBox1.Select(savedText.Length, 0);
}
Or would not worke with opening the drop down list, which is essential:
comboBox1.DropDownStyle = ComboBoxStyle.DropDown;
comboBox1.AutoCompleteMode = AutoCompleteMode.SuggestAppend;
comboBox1.AutoCompleteSource = AutoCompleteSource.ListItems;
Is there a way to just disable the "select first item" thing?
One way to achieve is to have custom user control.
You can have a TextBox overlapping your ComboBox.
So, user will be interacting with Textbox only, and as per text entered in TextBox(using appropriate Event - key press will be fine), you can query in database and load ComboBox with the result of query.
Related
I got a problem with a ListBox in a WinForm application. I have two ListBoxes inside of a tab control and depending on the selection in the first one (lb1), the DataSource of the second one (lb2) changes. This is done in the SelectedValueChanged Event.
private void listBox_ControlUnits_SelectedValueChanged(object sender, EventArgs e)
{
ControlUnit unit = (sender as ListBox).SelectedItem as ControlUnit;
textBox_ProjectNameTab.Text = unit.ProjectName;
listBox_ControlCircuits.DataSource = null;
listBox_ControlCircuits.DataSource = unit.ControlCircuits;
}
lb1 is filled with a DataSource, too.
Now if I select a value in lb1 the selection automatically jumps back to the first item and I can not figure out why. is this some kind of UI update problem?
Even without the SelectedValueChanged event and the connection to the second listbox the issue occures.
Short gif of the problem, sorry for the blurriness
If I select one item more than once it works somehow (as seen in the gif).
Edit:
I found the problem but I do not quite understand what happens.
I have another listBox on another tab of my tab control. This listBox has the same DataSource as lb1. This seems to cause this behavior.
I finally found the problem:
I did not know that if I use the same DataSource for two ListBoxes they share the BindingContext per default.
I created a new BindingContext for the second ListBox and now the selection does no longer change.
listBox_allGroups.DataSource = null;
listBox_allGroups.DataSource = x.y;
listBox_allGroups.DisplayMember = "Name";
listBox_ControlUnits.DataSource = null;
listBox_ControlUnits.DataSource = x.y;
listBox_ControlUnits.DisplayMember = "Name";
listBox_ControlUnits.BindingContext = new BindingContext();
You can use a variable to hold the selected item
object _selecteditem=null;
and check it in ListBox click event.
prive void ListBox1_Click(object sender,EventArgs e)
{
if(ListBox1.SelectItem == _selecteditem) return;
// do ...
}
I have five RadioButton and five ComboBox controls.
Each RadioButton is connected to a ComboBox.
When I activate one RadioButton, the corresponding ComboBox, it gets enabled.
Now when I choose another RadioButton, the information in the previously selected ComboBox should clear but does not!
I have tried with ComboBox.Clear() as well as ComboBox.Reset(), but it doesn't work.
Here is my code for one of the ComboBox and RadioButton
if (radioButtondinner.Checked == true)
{
comboBoxdinner.DataSource = DList.Dwork();
comboBoxdinner.DisplayMember = "dinner";
}
As I said in comment: you can use one Combobox and only to change data sources when you check other RadioButton that should work sure
But If you want to have more Combobox then just type in else statements
comboBox.DataSource = null;
// create a check change event and use this.
private void radioButtondinner_CheckedChanged(object sender, EventArgs e)
{
if (!radioButtondinner.Checked)
{
// if you want to clear only the text or selected item text
comboBoxdinner.Text = String.Empty;
// if you want to clear the entire data source
comboBoxdinner.DataSource = null;
}
}
How can i avoid the double click on a DropDownButton used within a DataGridView? Right now I am able to view the drop down items within the DataGridView by clicking two or more times. First time it selects the cell and second time when I click on the DropDownButton arrow, it shows the list. How can I achieve the same in a single click?
Set EditMode property of the DataGridView to EditOnEnter: link
DataGridView.EditMode - Gets or sets a value indicating how to begin editing a cell.
EditOnEnter - Editing begins when the cell receives focus.
You can achieve this by subscribing for the EditingControlShowing event of the grid and there for control of type ComboBox
ComboBox ctl = e.Control as ComboBox;
ctl.Enter -= new EventHandler(ctl_Enter);
ctl.Enter += new EventHandler(ctl_Enter);
And in the Enter event, use the property
void ctl_Enter(object sender, EventArgs e)
{
(sender as ComboBox).DroppedDown = true;
}
DroppedDown indicates as the name suggests whether the dropdown area is shown or not, so whenever the control is entered this will set it to true and display the items without the need of further clicks.
The "set EditMode property of the DataGridView to EditOnEnter" worked for me, but I found another problem: user can't delete a row by just selecting and pressing DEL key. So, a google search gave me another way to do it. Just catch the event CellEnter and check if the cell is the appropriated type to perform appropriated action like this sample code:
private void Form_OnLoad(object sender, EventArgs e){
dgvArmazem.CellEnter += new DataGridViewCellEventHandler(dgvArmazem_CellEnter);
}
void dgvArmazem_CellEnter(object sender, DataGridViewCellEventArgs e)
{
DataGridView dg = (DataGridView)sender;
if (dg.CurrentCell.EditType == typeof(DataGridViewComboBoxEditingControl))
{
SendKeys.Send("{F4}");
}
}
Now the ComboBox drops down faster and the user still delete a row by selecting a row and pressing DEL key.
That's it.
My windows form has an ADD button which adds a combo box to the form after each click. The problem is, i am not able to bind it to a table column at run time. Using an existing databinding source selects the same value in all the combo boxes. I am coding in C#
here is the sample code :
ComboBox ocbNext = new ComboBox();
//HAVE set the rest of the properties right, the problem is with the databinding
ocbNext.DataSource = this.dummysubjectBindingSource;
ocbNext.DisplayMember = "sub_name";
ocbNext.ValueMember = "sub_name";
this.Controls.Add(ocbNext);
I added a DataSet to the solution and droped the Employees table (from Northwind) in the designer, which automatically created the employeesBindingSource. I dropped a combobox and a button on the Form and I set the DataSource and DataMember of the combo. Then I handled some events:
private void Form1_Load(object sender, EventArgs e)
{
this.employeesTableAdapter.Fill(this.dS.Employees);
}
private int _i = 0;
private void button1_Click(object sender, EventArgs e)
{
ComboBox combo = new ComboBox();
combo.DataSource = this.employeesBindingSource;
combo.DisplayMember = this.dS.Tables[0].Columns[++_i].ColumnName;
combo.Location = new Point(comboBox1.Location.X, comboBox1.Location.Y + comboBox1.Height * _i);
this.Controls.Add(combo);
}
So on each click, a new combo is added onto the form dynamically right under the previous combo. The combo is also bound to the next column in the Employees table (no boundary checks however).
As you can see, this is pretty easy stuff. Hope this helps.
Okay, so here is a variation of the code that could help you with that other question you asked in the comments of this answer.
It assumes you have a Form with a button and a DataSet with table Employees. On button click it creates a combo, and fills it with data (the Name column of Employees). Each time you add a combo, it gets its own copy of the data (this is important to be able to remove items from one combo at a time). Then, every time you select a value in the combo, the combo is disabled and the other combos don't have that selected value in their list.
private int _i = 0;
private void button1_Click(object sender, EventArgs e)
{
DataSet dataS = dS.Clone();
this.employeesTableAdapter.Fill((DS.EmployeesDataTable)dataS.Tables[0]);
BindingSource bindSource = new BindingSource(dataS, "Employees");
ComboBox combo = new ComboBox();
combo.Name = this.dS.Tables[0].Columns[0].ColumnName + (++_i).ToString();
combo.DataSource = bindSource;
combo.DisplayMember = this.dS.Tables[0].Columns[1].ColumnName; //This column is the Name of Employee
combo.Location = new Point(button1.Location.X, button1.Location.Y + combo.Height * _i);
combo.SelectedIndexChanged += new EventHandler(comboBox_SelectedIndexChanged);
this.Controls.Add(combo);
}
private void comboBox_SelectedIndexChanged(object sender, EventArgs e)
{
foreach (Control ctrl in this.Controls)
{
if (ctrl is ComboBox && ctrl != sender && ctrl.Enabled)
{
((BindingSource)((ComboBox)ctrl).DataSource).RemoveAt(((ComboBox)sender).SelectedIndex);
}
}
((ComboBox)sender).Enabled = false;
}
This is pretty close to what you require, or easily adaptable to meet your expectations. Enjoy and please select an answer as the accepted one. Thanks!
Option 1: Fill the combobox with strings:
this.comboBox1.Items.Add("Syed");
this.comboBox1.Items.Add("Baqar");
Option 2: Fill the combobox with an array of strings:
this.comboBox1.Items.AddRange(new object[] { "Syed", "Baqar" });
You need to add controls to the parent window first, and then set the data source.
ComboBox ocbNext = new ComboBox();
this.Controls.Add(ocbNext);
ocbNext.DisplayMember = "sub_name";
ocbNext.ValueMember = "sub_name";
ocbNext.DataSource = this.dummysubjectBindingSource;
Should be fine if you create a new local ComboBox variable in the clickevent. If you use a global variable for the ComboBox this might explain your problems. But without a sample how you're doing it's hard to see what's really happening, so think this is just a rough guess
I want to use a ComboBox with the DropDownList style (the one that makes it look like a button so you can't enter a value) to insert a value into a text box. I want the combobox to have a text label called 'Wildcards' and as I select a wildcard from the list the selected value is inserted in to a text box and the combobox text remains 'Wildcard'. My first problem is I can't seem to set a text value when the combobox is in DropDownList style. Using the properties pallet doesn't work the text value is simply cleared when you click off, adding comboBox.Text = "Wildcards"; to form_load doesn't work either. Can anyone help?
The code you specify:
comboBox.Text = "Wildcards";
...should work. The only reason it would not is that the text you specify is not an item within the comboBox's item list. When using the DropDownList style, you can only set Text to values that actually appear in the list.
If it is the case that you are trying to set the text to Wildcards and that item does not appear in the list, and an alternative solution is not acceptable, you may have to be a bit dirty with the code and add an item temporarily that is removed when the drop-down list is expanded.
For example, if you have a form containing a combobox named "comboBox1" with some items and a button named "button1" you could do something like this:
private void button1_Click(object sender, EventArgs e)
{
if (!comboBox1.Items.Contains("Wildcards"))
{
comboBox1.Items.Add("Wildcards");
}
comboBox1.Text = "Wildcards";
}
private void comboBox1_DropDown(object sender, EventArgs e)
{
if (comboBox1.Items.Contains("Wildcards"))
comboBox1.Items.Remove("Wildcards");
}
That's pretty quick and dirty but by capturing the DropDownClosed event too you could clean it up a bit, adding the "Wildcards" item back as needed.
You can select one of items on formload or in form constructor:
public MyForm()
{
InitializeComponent();
comboBox.SelectedIndex = 0;
}
or
private void MyForm_Load(object sender, EventArgs e)
{
comboBox.SelectedIndex = 0;
}
Try this
comboBox1.SelectedValue = "Wildcards";
This may be a possible solution:
comboBox1.SelectedValue = comboBox1.Items.FindByText("Wildcards").Value;