I have databinding for my comboboxes set up like this: Show Enum Description Instead of Name
When I am trying to pull the data however, I can't just get the state code, such as IA. I get this long string like: { Value = IA, Description = Iowa }
When I pause the code and look at the combo box values, I am able to do stuff like State.SelectionBoxItem.Value That is an option that expands from the popup menu when you hover over the variable. I can't seem to ever just grab that value programatically though.
Is it a "feature" of visual studio to allow me to break that list down like that?
Is that a string that I will have to break down programatically?
My guess would be you are looking at SelectedItem property not SelectedValue. The string { Value = IA, Description = Iowa } is result of invocation of ToString method of an anonymous type, so yes it is a feature.
In code form another question SelectedValuePath property is not set to Value, which is required to get state code of ListBox selected item through SelectedValue property.
Related
I have a DataGridView in my .NET 4.5 WinForms app with two columns. One column is a regular textbox column and the other column is a DataGridViewComboBoxColumn that is a dropdown. I am trying to bind the columns to a BindingList of my Filter object and I would like everything inside of the enum FilterType to show up in the dropdown. Here's the code for my object and enum:
public class Filter
{
public string keyword { get; set; }
public FilterType type { get; set; }
}
public enum FilterType : int //the strings should appear in the dropdown
{
SESSION = 1,
ORDER = 2,
SHIPMENT = 3
}
I have manually created the columns in the VS 2012 designer where I changed the ColumnType, HeaderText, and DataPropertyName to keyword and type.
Using an answer I found here I have added these two lines of code to my form loading event:
colFilterType.DataSource = Enum.GetValues(typeof(FilterType));
colFilterType.ValueType = typeof(FilterType);
When I run the code I initially see a blank row. Whenever I click on the row, irregardless of which column is clicked, I get a pop-up error.
System.ArgumentException: DataGridViewComboBoxCell value is not valid. ... please handle the DataError event.
I can ignore it and type whatever text I want into the Keyword column, and the dropdown is magically filled in with the first value of the enum. However, if I even mouse-over the dropdown the error pops up again (please see the screenshot). I am not sure what causes the error and don't know where to set a breakpoint. I also do not know if I'm creating the problem by making parts of the DataGridView in the designer and modifying those in code. The designer does not let me set the DataSource the way I did in the code. It also contains a field ValueMember that I haven't seen used in code.
Although not ideal, I wouldn't mind catching the error and doing nothing with it since the dropdown seems to populate itself (and assuming all the data stays intact).
Your code works fine when adding the column at runtime. Sample code:
DataGridViewComboBoxColumn colFilterType = new DataGridViewComboBoxColumn();
colFilterType.HeaderText = "Name you want";
colFilterType.DataSource = Enum.GetValues(typeof(FilterType));
colFilterType.ValueType = typeof(FilterType);
dataGridView1.Columns.Add(colFilterType);
Errors like the one you report are usually provoked while changing the type of a cell/column at runtime, because of the big number of events which are triggered every time a DataGridView is affected in any way: some of them expect the old type and find elements with the new one (e.g., expecting an int and finding a string).
I have a method called void showdata() and If I do this...
textBox1.Text = ds.Tables[0].Rows[rno][0].ToString();
comboBox1.Text = ds.Tables[0].Rows[rno][1].ToString();
I am able to retrieve values from database but I am unable to retrieve value from radiobuttons e.g.
rBMale.Text = ds.Tables[0].Rows[rno][3].ToString();
by using navigation buttons.
When I say values I mean the green dot that you see from the application not the string value. I have named rBMale as radiobutton.
Does anyone know why that is?
Thanks
It is not clear, but it seems that you want to set the Checked property of the RadioButton.
rBMale.Checked = Convert.ToBoolean(ds.Tables[0].Rows[rno][3]);
This property is used to paint the RadioButton with the glyph to represent the value for true or for false
The Text property of radio buttons and check boxes is the on screen text that tells the user what the button is (in theory) and has little or nothing to do with its value. What you are probably looking for is the Checked property, which is a bool.
try something along these lines:
rBMale.Checked = Convert.ToBoolean(ds.Tables[0].Rows[rno][3]);
I have some code that will open a sqllite database, get some street names, and populate a list box that is then attached to a combo-box so it can suggest the names as the user types them. I want to make a procedure that I can call to do this since it will be used on may different combo-boxes. I can pass it the name of the control, but how do I modify attributes of a contol while referring to it as a variable?
Something like:
string A = "cbSTreets"
[A].text = "Sets the Text for the combo box."
If someone could just point me in the right direction I would appreciate it.
Instead of passing it as the name of a control, why not just pass the control itself (especially if they're all comboboxes and the same type?)
Alternatively if for some reason you can't pass the control itself, you could set something up with a datastructure like a dictionary if you need to use the string name:
Dictionary<string, ComboBox> comboBoxes = new Dictionary<string, ComboBox>();
//Use the string you want to refer to the combobox and the combobox item itself
comboBoxes.Add("bcbsTreets", comboBox1);
//Use the name as defined in the previous step to get the reference to the combobox and
//set the text
comboBoxes["bcbsTreets"].Text = "whatever";
You could try something like this:
private void SetText(List<string> streets, ComboBox cb)
{
cb.DataSource = streets;
}
Of course, you'll need to fill the streets from your database and pass in the ComboBox control you want to populate. You can use another collection if you like, but ComboBox datasources need to implement the IList interface.
This is only possible via reflection and should be avoided!
You should do this the normal way.
For the solution how to do it with reflection, look here: How to access class member by string in C#?
I'm working on a GUI that allows the user to manipulate xml files. I display the xml file in a datagridview organized neatly by columns through xml elements. I allow the user to add columns as an extention on my project. The column gets added to the dataset table, then updated to the datagridveiew that I use to display the xml file in. I've included the ability for the user to add a combobox column to select choices instead of entering them in constantly like.. true or false. However, that is where the problem lies. Saving a normal column was easy. The combobox column is being a pain.
I have a "save combobox column" to have it updated to the xml and a "save" button to save in a destination of the user's choice.
I've done some research and it seems like the combobox class has such a feature to gain access to the selecteditem in the combobox put in by the user.
Where we have:
ComboBox box = new ComboBox();
box.SelectedItem;
I tried applying this to the combobox column class but it does not have such a function. Thus, I cannot figure out how to directly obtain the value of the user's selected item. I tried experimenting with comboboxcell's as well, but that didn't lead me anywhere either. Both those classes I played around with do not have a... "selected item" function and even google does not have a solution for me. =( I've also tried using the cell.value, but it is "null" for some reason. Even when the user selects an item in the box, it doesn't get saved into the cell's value.
TLDR:
My question in short is, how, if possible, do you gain access to the comboboxcolumn cell's selected item? Additionally, how would you then ensure that the item value is saved in the cell?
Thanks in advance. I'm using .NET 3.5 SP1, through Visual Studio 2008 C#.
Sincerely,
tf.rz
The Control in a DataGridView is not a ComboBox, it is a DataGridViewComboBox and has different properties and methods. From MSDN
Unlike the ComboBox control, the DataGridViewComboBoxCell does not have SelectedIndex and SelectedValue properties. Instead, selecting a value from a drop-down list sets the cell Value property.
However, you mentioned that the Cell.Value is null for you. Well there may be another step you are missing according to the following article (How to: Access Objects in a Windows Forms DataGridViewComboBoxCell Drop-Down List).
You must set the DataGridViewComboBoxColumn.ValueMember or DataGridViewComboBoxCell.ValueMember property to the name of a property on your business object. When the user makes a selection, the indicated property of the business object sets the cell Value property.
If we have bound a datagridcomboboxcell with a different DisplayMember and ValueMember, like so:
dgcombocell.DisplayMember = "Name";
dgcombocell.ValueMember = "Id";
dgcombocell.DataSource = dataset1.Tables[0];
Then for getting SelectedText, and SelectedValue, we can write this code:
string SelectedText = Convert.ToString((DataGridView1.Rows[0].Cells["dgcombocell"] as DataGridViewComboBoxCell).FormattedValue.ToString());
int SelectedVal = Convert.ToInt32(DataGridView1.Rows[0].Cells["dgcombocell"].Value);
I hope it solves your problem.
Use this to get or set selected value:
object selectedValue = currentRow.Cells["comboboxColumnName"].Value
Don't forget to set DisplayMember and ValueMember for your DataGridViewComboBoxColumn
This is how it is done
DataGridViewComboBoxCell comboCell = (DataGridViewComboBoxCell)dgv.Rows[0].Cells[1];
MessageBox.Show(""+comboCell.Items.IndexOf(comboCell.Value));
A .Net combox is actually a composite control made up of a textbox and a dropdownlist. Use box.Text to get the currently displayed information.
EDIT: The row or the cell should have a .FindControl() method. You'll need to do something like:
Combobox box = (Combobox)(row.FindControl("[combobox ID]"));
string val = box.Text;
Basically, you're finding the control within its container (row or cell), then casting the control found as a combobox, then accessing its .Text property.
I use this:
private int GetDataGridViewComboBoxCellSelectedIndex(DataGridViewCell d)
{
return ((DataGridViewComboBoxCell)d).Items.IndexOf(d.Value);
}
Edit 1
I believe my problem stems from the following. The function that fills the dropdown portion sets the Display Member to the CountyName. Then when I try and set the SelectedText or EditValue, as has been suggested, that function only returns the CountyID which it try's to match to something in the DropDown list DisplayMember. I need it to match it to something in the ValueMember list.
Using the following I got it to work but it is a HACK and I'd greatly appreciate finding a real solution.
lkuResidenceCounty.ItemIndex = Convert.ToInt32(row["ResidencyCountyID"].ToString());
Original Post
I have a lookup box(DevExpress) on a member form that I fill the possible values in from the DB with this code -->
lkuResidenceCounty.Properties.DataSource = ConnectBLL.BLL.Person.CountyList();
lkuResidenceCounty.Properties.PopulateColumns();
lkuResidenceCounty.Properties.DisplayMember = "CountyName";
lkuResidenceCounty.Properties.ValueMember = "CountyID";
lkuResidenceCounty.Properties.Columns[0].Visible = false;
lkuResidenceCounty.Properties.Columns[2].Visible = false;
lkuResidenceCounty.Properties.Columns[3].Visible = false;
This works just fine as the CountyName is displayed as expected.
However, When I try and load an existing member's value for this field using the below, which is part of a function that takes a row from the DataSet -->
lkuResidenceCounty.Properties.ValueMember = row["ResidencyCountyID"].ToString();
I get a blank box. I have stepped through the code and the correct ID is being returned for the member.
Unfortunately the stored procedure to fill the dropdown options pulls from a Maintenance Table with the columns "CountyName" & "CountyID". So that is correct. Unfortunately, the stored procedure to load a specific person's current county pulls from the Person Table where there is a column called "ResidencyCountyID". It is so named because there is also a "ResponsibilityCountyID" column.
I need a way for them both to coexist, any solutions?
Thanks!
DisplayMember and ValueMember are used to populate the control with the list of selectable values. To set the selected value of a populated LookUpEdit control, set its EditValue property:
lkuResidenceCounty.EditValue = row["ResidencyCountyID"].ToString();
In response to your edit: According to the documentation:
The currently selected row determines values for the editor's edit value and display text. The value for BaseEdit.EditValue is obtained from the RepositoryItemLookUpEditBase.ValueMember field, while the text to display in the edit box is obtained from the RepositoryItemLookUpEditBase.DisplayMember field of the selected row.
When you change BaseEdit.EditValue,
the editor locates and selects the row
whose
RepositoryItemLookUpEditBase.ValueMember
field contains the new value. The text
in the edit box is changed to reflect
the newly selected row.
I don't use these controls but it sounds to me that it shouldn't be working as you described. I think the ToString() is the problem because EditValue accepts an object so it's probably expecting an int for the value. Try:
lkuResidenceCounty.EditValue = (int)row["ResidencyCountyID"];
The ValueMember property tells the list what field to pull from when setting the Value property. Once you've set the ValueMember to "CountyID", then when the list is Databound, it will set all the list items' value properties to their respect objects' CountyID fields.
Hence, you should not do:
lkuResidenceCounty.Properties.ValueMember = row["ResidencyCountyID"].ToString();
but rather
lkuResidenceCounty.Properties.ValueMember = "CountyID";
was perfectly fine, as long as you've correctly identified the field you're trying to databind. Once the list get's databound you should see the results you're expecting.
However, after looking at your code, it seems that you're mismatching your field. In one place you're using ResidencyCountyID and in another you're using CountyID. That is most likely your source of confusion. Figure out what the actual field name is and make sure you set the ValueMember to that.
UPDATE
After reading your comment, what your looking for is the SelectedValue property. The SelectedValue property tells the list to force the selected value to whatever input you give it.
Essentially you have two things going on here. ValueMember tells the list what to use as the value from your data source, and SelectedValue which tells the list what the currently selected value should be.
Why is it that you need the same LookUpEdit to have two value members? Is it being used standalone or in a grid? If standalone, you could swap out the two repository editors depending on the current row. But, are there more than 2 possible values for the ValueMember? That would also complicate things.
UPDATE
Looking at your edit, I think I understand what's going on a little more. So, you don't wish to change your ValueMember (which refers to a data column), but rather to change the value of the editor? If so, then you should definitely use EditValue (not SelectedText, which I don't believe is meant to be set), and assign it to row["value_field"] like so:
lkuResidenceCounty.EditValue = row["ResidencyCountyID"];
What happens when you do that?