I create method that when a user selects a db table from the combobox, a number of new comboboxes will be generated with each of them shows the table column name. The problem is when I select the second or third db table, the column names associated with those tables are not showed. Instead, the columns of the first table remain exist. Could someone suggest how to remove the comboboxes from the previous selection and show the new ones?
private void cboTable_SelectedIndexChanged(object sender, EventArgs e)
{
string tableName = cboTable.SelectedItem.ToString();
List<string> columnList = GetDatabaseList(tableName);
int i = 0;
foreach (var column in columnList)
{
ComboBox cb = new ComboBox();
cb.Location = new Point(475, 25 * i + 235);
this.Controls.Add(cb);
cb.Items.Add(column);
cb.SelectedIndex = -1;
cb.Refresh();
cb.SelectedIndex = 0;
i++;
}
}
I have a DataGridView in a C# WinForms project in which, when the user clicks on certain DGV cells, the cell changes to a DataGridViewComboBoxCell and the ComboBox is populated with some values for the user to select. Here's the form code for the DataGridView_Click event:
private void dgvCategories_Click(Object sender, DataGridViewCellEventArgs e)
{
if (e.ColumnIndex == 5 && !(dgvCategories.Rows[e.RowIndex].Cells[e.ColumnIndex].GetType().Name == "DataGridViewComboBoxCell"))
{
// Bind combobox to dgv and than bind new values datasource to combobox
DataGridViewComboBoxCell cboNewValueList = new DataGridViewComboBoxCell();
// Get fields to build New Value query
List<string> lsNewValuesResult = new List<string>();
string strCategory = dtCategories.Rows[e.RowIndex][1].ToString();
string strCompanyName = cboSelectCompany.Text;
string strQueryGetNewValuesValidationInfo = "SELECT validationdb, validationtable, validationfield, validationfield2, validationvalue2" +
" FROM masterfiles.categories" +
" WHERE category = #category";
//" WHERE category = '" + strCategory + "'";
// Pass validation info query to db and return list of New Values
db getListOfNewValues = new db();
lsNewValuesResult = getListOfNewValues.GetNewValuesList(strQueryGetNewValuesValidationInfo, strCategory, strCompanyName);
//Populate the combobox with the list of New Values
foreach (string strListItem in lsNewValuesResult)
{
cboNewValueList.Items.Add(strListItem);
}
//
dgvCategories[e.ColumnIndex, e.RowIndex] = cboNewValueList;
}
}
Here's the code in the db class that populates the ComboBox (this likely isn't necessary to include for the purposes of this question, but for the sake of completeness, I'm including it, in case is it relevant):
public List<string> GetNewValuesList(string strValidationInfoQuery, string strCategory, string strCompanyName)
{
List<string> lsValidationInfo = new List<string>();
List<string> lsNewValuesList = new List<string>();
using (NpgsqlConnection conn = new NpgsqlConnection(connString))
using (NpgsqlCommand cmd = new NpgsqlCommand(strValidationInfoQuery, conn))
{
cmd.Parameters.AddWithValue("category", strCategory);
conn.Open();
using (NpgsqlDataReader reader = cmd.ExecuteReader())
{
while (reader.Read())
{
int intReaderIndex;
for (intReaderIndex = 0; intReaderIndex <= reader.FieldCount - 1; intReaderIndex++)
{
// reader indexes 3 & 4 correspond to categories.validationfield2 and validationvalue2, which can be null
if (string.IsNullOrEmpty(reader[intReaderIndex].ToString()))
{
lsValidationInfo.Add("");
}
else
{
lsValidationInfo.Add(reader.GetString(intReaderIndex));
}
//Console.WriteLine("reader index " + intReaderIndex + ": " + reader.GetString(intReaderIndex));
}
}
}
}
string strValidationDb = lsValidationInfo[0];
string strValidationTable = lsValidationInfo[1];
string strValidationField = lsValidationInfo[2];
string strValidationField2 = lsValidationInfo[3];
string strValidationValue2 = lsValidationInfo[4];
string strQueryGetNewValues = "SELECT DISTINCT " + strValidationField +
" FROM " + strValidationDb + "." + strValidationTable +
" WHERE company_id = (SELECT id FROM company WHERE name = '" + strCompanyName + "')";
if (!string.IsNullOrEmpty(strValidationField2) && !string.IsNullOrEmpty(strValidationValue2)) strQueryGetNewValues += " AND " + strValidationField2 + " = '" + strValidationValue2 + "'";
strQueryGetNewValues += " ORDER BY " + strValidationField;
using (NpgsqlConnection conn = new NpgsqlConnection(connString))
using (NpgsqlCommand cmd = new NpgsqlCommand(strQueryGetNewValues, conn))
{
conn.Open();
using (NpgsqlDataReader reader = cmd.ExecuteReader())
{
while (reader.Read())
{
int intReaderIndex;
for (intReaderIndex = 0; intReaderIndex <= reader.FieldCount - 1; intReaderIndex++)
{
// reader indexes 3 & 4 correspond to categories.validationfield2 and validationvalue2, which can be null
if (string.IsNullOrEmpty(reader[intReaderIndex].ToString()))
{
lsNewValuesList.Add("");
}
else
{
lsNewValuesList.Add(reader.GetString(intReaderIndex));
}
Console.WriteLine("reader index " + intReaderIndex + ": " + reader.GetString(intReaderIndex));
}
}
}
}
return lsNewValuesList;
}
The combobox is getting populated, as I can access the items in lsNewValuesResult in the _Click method. The DGV Edit Mode is set to EditOnEnter. I tried EditOnKeystroke, but that didn't cause the combobox to expand on mouse click.
This is what the combobox looks like when the cell is clicked on and the CBO is populated and added to the DGV cell:
That's after I clicked each of the two cells.
[RESOLVED]
See my Answer below.
Unfortunately solving this revealed a new issue.
I'm about to publicly admit that I'm stupid:
For design and functionality reasons that are required for this project, I am manually setting the widths and names of the DGV's columns, and I also need the 2nd through 4th columns ReadOnly = true. Well, I inadvertently set the 5th column - the column that this question is about to ReadOnly = true as well.
Thank you all for your attempts at answering. This just serves to remind us how something so simple can cause a seemingly big issue and is so easy to overlook!
If I recognize your problem correctly, in my test app i add a DataGridView whit 6 column, EditMode = EditOnEnter
(Others need three time click to open dropdown, As far as I tried) and handle CellStateChanged envent.
private void dgvCategories_CellStateChanged(object sender, DataGridViewCellStateChangedEventArgs e)
{
if (e.StateChanged == DataGridViewElementStates.Selected)
{
DataGridViewCell cell = e.Cell;
int columnIndex = cell.ColumnIndex;
int rowIndex = cell.RowIndex;
//---IF CONDITIONS--
//columnIndex == 5
// Only cells in Columns[5]
//cell.Selected
// Because this event raised two time, first for last selected cell and once again
// for currently selected cell and we need only currently selected cell.
//cell.EditType.Name != "DataGridViewComboBoxEditingControl"
// If this cell "CellStateChanged" raised for second time, only other cell types allowed
// to edit, otherwise the current cell lost last selected item.
if (columnIndex == 5 && cell.Selected && cell.EditType.Name != "DataGridViewComboBoxEditingControl")
{
DataGridViewComboBoxCell cboNewValueList = new DataGridViewComboBoxCell();
//Add items to DataGridViewComboBoxCell for test, replace it with yours.
for (int i = 0; i < 10; i++)
cboNewValueList.Items.Add($"Item {i}");
dgvCategories[columnIndex, rowIndex] = cboNewValueList;
}
}
}
NOTE: user must click two time in a cell to open drop down menu.
Edit One: As Reza Aghaei suggest for single click in cell:
private void dgvCategories_CellClick(object sender, DataGridViewCellEventArgs e)
{
DataGridViewComboBoxEditingControl editingControl = dgvCategories.EditingControl as DataGridViewComboBoxEditingControl;
if (editingControl != null)
editingControl.DroppedDown = true;
}
You might need to turn AutoGenerateColumns off:
Also, it seems to take a three clicks for the dropdown to pop.
public Form1()
{
InitializeComponent();
dataGridView1.AutoGenerateColumns = false;
dataGridView1.DataSource = GetDataSource();
DataGridViewComboBoxColumn dgvcbc = new DataGridViewComboBoxColumn();
dgvcbc.Items.Add("R0C0");
dgvcbc.Items.Add("R1C0");
dgvcbc.Items.Add("R2C0");
dgvcbc.Items.Add("R3C0");
dgvcbc.DataPropertyName = "Col0";
dataGridView1.Columns.Add(dgvcbc);
}
DataTable GetDataSource()
{
var dtb = new DataTable();
dtb.Columns.Add("Col0", typeof(string));
dtb.Columns.Add("Col1", typeof(string));
dtb.Columns.Add("Col2", typeof(string));
dtb.Columns.Add("Col3", typeof(string));
dtb.Columns.Add("Col4", typeof(string));
dtb.Rows.Add("R0C0", "R0C1", "R0C2", "R0C3", "R0C4");
dtb.Rows.Add("R1C0", "R1C1", "R1C2", "R1C3", "R1C4");
dtb.Rows.Add("R2C0", "R2C1", "R2C2", "R2C3", "R2C4");
dtb.Rows.Add("R3C0", "R3C1", "R3C2", "R3C3", "R3C4");
return dtb;
}
Are you maybe getting an error which is not being shown for some reason?
If I use your code, DataGridViewComboBoxCell seems to be populated with values, but I get DataGridViewComboBoxCell value is not valid runtime error.
This test code is working fine for me:
private void dgvCategories_CellContentClick(object sender, DataGridViewCellEventArgs e)
{
DataGridViewComboBoxCell cboNewValueList = new DataGridViewComboBoxCell();
List<string> lsNewValuesResult = new List<string>();
lsNewValuesResult.Add("Value1");
lsNewValuesResult.Add("Value2");
lsNewValuesResult.Add("Value3");
foreach (string strListItem in lsNewValuesResult)
{
cboNewValueList.Items.Add(strListItem);
}
dgvCategories[e.ColumnIndex, e.RowIndex] = cboNewValueList;
// Added setting of initial value
cboNewValueList.Value = cboNewValueList.Items[0];
}
So maybe try setting the initial value for your DataGridViewComboBoxCell after you add it to the DataGridView.
You can consider the following facts about DataGridView:
If you set AutoGenerateColumns to false, then you need to add columns to Columns collection manually.
If you set AutoGenerateColumns to true, when you assign the data to DataSource, the control generates columns automatically for the data source. In this case, the control looks in list of columns of the data source and for each column if there's no column in the Columns collection of the control having the same DataPropertyName as data source's column name, it will add a column to Columns collection.
DataPropertyName of the datagridviews' columns determines the bound column of the data source.
You usually want to add DataGridViewXXXXColumn to columns collection rather than using a DataGridViewXXXXCell for a cell.
If you set EditMode to EditOnEnter, then if you click on dropdown button, one click is enough. If you click on cell content, two clicks is needed.
If you would like to make it single click even if you click on cell content, take a look at this post. (Note: I haven't used this is the example, it's a bit annoying.)
you can set DisplayStyle to Nothing, then it shows the column as a combo box, just in edit mode.
A basic example on using DataGridViewComboBoxColumn
I suppose you are going to show a list of Products having (Id, Name, Price, CategoryId) in a DataGridView and the CategoryId should come from a list of Categories having (Id, Name) and you are going to show CategoryId as a ComboBox.
In fact it's a basic and classic example of DataGridViewComboBoxColumn:
private void Form1_Load(object sender, EventArgs e) {
var categories = GetCategories();
var products = GetProducts();
var idColumn = new DataGridViewTextBoxColumn() {
Name = "Id", HeaderText = "Id", DataPropertyName = "Id"
};
var nameColumn = new DataGridViewTextBoxColumn() {
Name = "Name", HeaderText = "Name", DataPropertyName = "Name"
};
var priceColumn = new DataGridViewTextBoxColumn() {
Name = "Price", HeaderText = "Price", DataPropertyName = "Price"
};
var categoryIdColumn = new DataGridViewComboBoxColumn() {
Name = "CategoryId", HeaderText = "Category Id", DataPropertyName = "CategoryId",
DataSource = categories, DisplayMember = "Name", ValueMember = "Id",
DisplayStyle = DataGridViewComboBoxDisplayStyle.Nothing
};
dataGridView1.Columns.AddRange(idColumn, nameColumn, priceColumn, categoryIdColumn);
dataGridView1.EditMode = DataGridViewEditMode.EditOnEnter;
dataGridView1.AutoGenerateColumns = false;
dataGridView1.DataSource = products;
}
public DataTable GetProducts() {
var products = new DataTable();
products.Columns.Add("Id", typeof(int));
products.Columns.Add("Name", typeof(string));
products.Columns.Add("Price", typeof(int));
products.Columns.Add("CategoryId", typeof(int));
products.Rows.Add(1, "Product 1", 100, 1);
products.Rows.Add(2, "Product 2", 200, 2);
return products;
}
public DataTable GetCategories() {
var categories = new DataTable();
categories.Columns.Add("Id", typeof(int));
categories.Columns.Add("Name", typeof(string));
categories.Rows.Add(1, "Category 1");
categories.Rows.Add(2, "Category 2");
return categories;
}
Learn more
To learn more about DataGridView, take a look at DataGridView Control (Windows Forms). It contains links to some documentations and useful How To articles, including:
DataGridView Control Overview
Basic Column, Row, and Cell Features in the Windows Forms DataGridView Control
Basic Formatting and Styling in the Windows Forms DataGridView Control
Column Types in the Windows Forms DataGridView Control
I'm trying to set a combobox value dynamically from a query with the following code and it's displayed only when I click on the combobox column, if I don't click the value disappears and it's not set.
The first 5 values are related to the user and the one displayed on the combobox might be not set into database, so it might be null if it doesn't exist or Type "A" or "C".
This is image is before clicking on the cell
This image is after clicking the cell with data loaded
This image is after the cell is unclicked and selected any other cell
//This code is used to Build combobox column after the data is binded
var items = new[] { new Logica.Items { valor = "C", texto = "Creador" }, new Logica.Items { valor = "A", texto = "Aprobador" } };
DataGridViewComboBoxColumn cell = new DataGridViewComboBoxColumn();
cell.DataSource = items;
cell.ValueMember = "valor";
cell.DisplayMember = "texto";
this.dataGridView1.Columns.Insert(5, cell);
this.dataGridView1.Columns[5].HeaderText = "TipoUsuario";
for (int i = 0; i < this.dataGridView1.RowCount; i++)
{
string valor = dataGridView1[0, i].Value.ToString();//get the first datagridview value
if (valor != null || valor != "")
{
string orgv = string.Empty + this.dataGridView1[0, i].Value.ToString().ToUpper();//required to fill combobox conditions
string veg = string.Empty + this.dataGridView1[1, i].Value.ToString().ToUpper();//required to fill combobox conditions
string aprobador = string.Empty + this.dataGridView1[3, i].Value.ToString().ToUpper();//required to fill combobox conditions
DataTable ds = cargarnodos("LLenaTipoUsuario"); // this query into db to get the combobox values if this exists, if not then it's null.
foreach (DataRow datar in ds.Rows)
{
if (orgv == datar["VKORG"].ToString() && veg == datar["VTWEG"].ToString() && aprobador == datar["idAprobador"].ToString())
{
string seleccion = datar["TipoUsuario"].ToString().ToUpper();
this.dataGridView1[5, i].Value = seleccion; // this changes value
MessageBox.Show(dataGridView1[5, 0].Value.ToString());
break;
}
}
}
I managed to get the rows to display the data in the cell even if the row is selected or not. This was done by setting the DataPropertyName of the ComboBoxColumn.
cell.DataPropertyName = "valor"; //
This should be data column should be available in corresponding to the Datasource of the parent DataGridView and their data types are identical..
Further if this column in the can contain null, you add the following line (if you are allowing the user to select/change etc)
cell.DefaultCellStyle.NullValue = "-- Select -- ";
In my case, while loading the form is not possible to set the combobox values. After the datagridview is binded, it's needed to use the following command to edit values based on previous selections.
dataGridView1.DataBindingComplete += new DataGridViewBindingCompleteEventHandler(selecciongv_DataBindingComplete); // selecciongv is the method to do the same proccess.
I want to display grid with multiple columns (like in RepositoryItemGridLookUpEdit) after click on cell in column, but if user don't want to pick item from grid, he can write something else (like in RepositoryItemComboBox). How to combine this two features?
//user can write, but only one column
RepositoryItemComboBox cbeMaterialy = new RepositoryItemComboBox();
DataTable dt = Getdt();
cbeMaterialy.Items.Clear();
foreach(DataRow item in dt.Rows)
{
cbeMaterialy.Items.Add(item);
}
gvView.Columns["ColumnName"].ColumnEdit = cbeMaterialy;
//user cannot write but multiple columns
RepositoryItemGridLookUpEdit editor = new RepositoryItemGridLookUpEdit();
editor.DataSource = dt;
column.ColumnEdit = editor;
//SOLUTION!
I mixed some answer from Devexpress team and came up with this:
public class Main()
{
//user can choose element from DB or write new value
RepositoryItemGridLookUpEdit riglue = new RepositoryItemGridLookUpEdit();
MyGridLookupDataSourceHelper.SetupGridLookUpEdit(riglue, GetMaterialyDataView(), "Kod", "Kod");
elementsEditGrid.gvView.Columns[ColumnName].ColumnEdit = riglue;
}
///////////////////
public class MyGridLookupDataSourceHelper
{
RepositoryItemGridLookUpEdit edit;
public MyGridLookupDataSourceHelper(RepositoryItemGridLookUpEdit edit, ITypedList dataSource, string displayMember, string valueMember)
{
this.edit = edit;
//enable writing into RepositoryItemGridLookUpEdit
edit.TextEditStyle = DevExpress.XtraEditors.Controls.TextEditStyles.Standard;
edit.DataSource = dataSource;
edit.DisplayMember = displayMember;
edit.ValueMember = valueMember;
edit.ProcessNewValue += edit_ProcessNewValue;
AddExistingValuesToDataSource();
}
public static void SetupGridLookUpEdit(RepositoryItemGridLookUpEdit edit, ITypedList dataSource, string displayMember, string valueMember)
{
new MyGridLookupDataSourceHelper(edit, dataSource, displayMember, valueMember);
}
//Add new values to temporary data source (not to DataBase!)
void edit_ProcessNewValue(object sender, DevExpress.XtraEditors.Controls.ProcessNewValueEventArgs e)
{
GridLookUpEdit lookUp = sender as GridLookUpEdit;
RepositoryItemGridLookUpEdit ri = lookUp.Properties;
DataTable dt = (ri.DataSource as DataView).Table;
DataRow row = dt.NewRow();
row[ri.DisplayMember] = e.DisplayValue;
row[ri.ValueMember] = e.DisplayValue;
dt.Rows.Add(row);
ri.View.RefreshData();
e.Handled = true;
//if user wants to add new values to database (data source)
//INSERT INTO DataSourceTable (ColumnName) VALUES (e.DisplayValue)
}
//Adds to temporary data source values already stored in RepositoryItemGridLookUpEdit (in case values aren't from DB)
void ProcessExistingValues(RepositoryItemGridLookUpEdit sender, object value)
{
RepositoryItemGridLookUpEdit ri = sender;
DataTable dt = (ri.DataSource as DataView).Table;
DataRow row = dt.NewRow();
row[ri.DisplayMember] = value;
row[ri.ValueMember] = value;
dt.Rows.Add(row);
ri.View.RefreshData();
}
private void AddExistingValuesToDataSource()
{
//SELECT from DB values that are already in riglue and add them to TEMPORARY DATA SOURCE (in case values aren't from DB)
//DataView dataView = SELECT ColumnName FROM table WHERE rowID = XXX
foreach (DataRow row in dataView.AsEnumerable())
{
string kod = (string)row["ColumnName"];
ProcessExistingValues(this.edit, kod);
}
}
}
You can set the RepositoryItemGridLookUpEdit.TextEditStyle property to Standard and you will be able to type. When a user types something different from what is contained in the lookup data source, the RepositoryItemGridLookUpEdit.ProcessNewValue event will be raised. In the event handler, you can add a new value to the data source to use it further.
RepositoryItemComboBox doesn't has DataSourse property, which allow to bind table with multiple column.
ComboBoxEdit Has DataSourse property, So you can bnd table with multiple column, OR create multiple column.
I'm new to C# and .NET
I need to display the matching name of a value in a databound DatagridViewComboBox, but I can't figure out how to do that.
I have the following code:
bs = new BindingSource();
bs.DataSource = typeof(CR);
dataGridView1.AutoGenerateColumns = false;
Column1.Width = 400;
Column1.DataPropertyName = "CR_NAME";
Column2.DataPropertyName = "CR_STATE_S";
Column2.ValueMember = "CR_STATE_S";
Column2.DisplayMember = "GetStateName";
Column2.Items.Add("0"); // how to set the matching value here?
Column2.Items.Add("1");
Column2.Items.Add("2");
dataGridView1.DataSource = bs;
GetStateName is a property of the CR Class that returns the matching name of the CR state. I need to display the state name in the combo box. How to do that? Thanks.
If you want to display something different from the values the cells shall contain, then you can't simply load one thing into the Items of the ComboBoxCells.
Instead you need a DataSource that has at least different fields for the two things you want to use:
A field for the visible representation of the data, called DisplayMember
And a field for the actual data values, called ValueMember
These fields can sit in a DataTable but you can also use any other collection with suitable properties.
Lets create a very simple class and have a List of that class:
class itemClass
{
public string display { get; set;}
public string value { get; set; }
public itemClass(string d, string v)
{ display = d; value = v;}
}
List<itemClass> myItems = new List<itemClass>();
private void loadButton_Click(object sender, EventArgs e)
{
// load the list with all values:
myItems.Add(new itemClass("zero", "0"));
myItems.Add(new itemClass("one", "1"));
myItems.Add(new itemClass("two", "2"));
myItems.Add(new itemClass("three", "3"));
myItems.Add(new itemClass("four", "4"));
myItems.Add(new itemClass("five", "5"));
myItems.Add(new itemClass("six", "6"));
// prepare the DataGridView 'DGV':
DGV.Columns.Clear();
DataGridViewComboBoxCell cCell = new DataGridViewComboBoxCell();
DataGridViewComboBoxColumn cCol = new DataGridViewComboBoxColumn();
DGV.Columns.Add(cCol);
cCol.DisplayMember = "display";
cCol.ValueMember = "value";
cCol.DataSource = myItems;
cCol.ValueType = typeof(string);
// add a few rows, for testing:
DGV.Rows.Add(7);
for (int i = 0; i < DGV.Rows.Count;
i++) DGV.Rows[i].Cells[0].Value = i + "";
}
In the example I load the Items manually. Usually you will want to pull the values from the database or some other source. You can do that either by loading the datasource list as above or you can have a lookup table either independently or in in a DataSet.
If all cells need to have individual lookup values you need to load them separately and not use the column but each of the cells cast to DataGridViewComboBoxCell.