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DataGridViewComboBoxColumn Class

Represents a column of DataGridViewComboBoxCell objects.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

[ToolboxBitmapAttribute(typeof(DataGridViewComboBoxColumn), "DataGridViewComboBoxColumn.bmp")]
public class DataGridViewComboBoxColumn : DataGridViewColumn

The DataGridViewComboBoxColumn type exposes the following members.

  NameDescription
Public methodDataGridViewComboBoxColumnInitializes a new instance of the DataGridViewTextBoxColumn class to the default state.
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  NameDescription
Public propertyAutoCompleteGets or sets a value indicating whether cells in the column will match the characters being entered in the cell with one from the possible selections.
Public propertyAutoSizeModeGets or sets the mode by which the column automatically adjusts its width. (Inherited from DataGridViewColumn.)
Public propertyCellTemplateGets or sets the template used to create cells. (Overrides DataGridViewColumn.CellTemplate.)
Public propertyCellTypeGets the run-time type of the cell template. (Inherited from DataGridViewColumn.)
Public propertyContextMenuStripGets or sets the shortcut menu for the column. (Inherited from DataGridViewColumn.)
Public propertyDataGridViewGets the DataGridView control associated with this element. (Inherited from DataGridViewElement.)
Public propertyDataPropertyNameGets or sets the name of the data source property or database column to which the DataGridViewColumn is bound. (Inherited from DataGridViewColumn.)
Public propertyDataSourceGets or sets the data source that populates the selections for the combo boxes.
Public propertyDefaultCellStyleGets or sets the column's default cell style. (Inherited from DataGridViewColumn.)
Public propertyDefaultHeaderCellTypeGets or sets the run-time type of the default header cell. (Inherited from DataGridViewBand.)
Public propertyDisplayedGets a value indicating whether the band is currently displayed onscreen. (Inherited from DataGridViewBand.)
Public propertyDisplayIndexGets or sets the display order of the column relative to the currently displayed columns. (Inherited from DataGridViewColumn.)
Public propertyDisplayMemberGets or sets a string that specifies the property or column from which to retrieve strings for display in the combo boxes.
Public propertyDisplayStyleGets or sets a value that determines how the combo box is displayed when not editing.
Public propertyDisplayStyleForCurrentCellOnlyGets or sets a value indicating whether the DisplayStyle property value applies only to the current cell in the DataGridView control when the current cell is in this column.
Public propertyDividerWidthGets or sets the width, in pixels, of the column divider. (Inherited from DataGridViewColumn.)
Public propertyDropDownWidthGets or sets the width of the drop-down lists of the combo boxes.
Public propertyFillWeightGets or sets a value that represents the width of the column when it is in fill mode relative to the widths of other fill-mode columns in the control. (Inherited from DataGridViewColumn.)
Public propertyFlatStyleGets or sets the flat style appearance of the column's cells.
Public propertyFrozenGets or sets a value indicating whether a column will move when a user scrolls the DataGridView control horizontally. (Inherited from DataGridViewColumn.)
Public propertyHasDefaultCellStyleGets a value indicating whether the DefaultCellStyle property has been set. (Inherited from DataGridViewBand.)
Public propertyHeaderCellGets or sets the DataGridViewColumnHeaderCell that represents the column header. (Inherited from DataGridViewColumn.)
Protected propertyHeaderCellCoreGets or sets the header cell of the DataGridViewBand. (Inherited from DataGridViewBand.)
Public propertyHeaderTextGets or sets the caption text on the column's header cell. (Inherited from DataGridViewColumn.)
Public propertyIndexGets the relative position of the band within the DataGridView control. (Inherited from DataGridViewBand.)
Public propertyInheritedAutoSizeModeGets the sizing mode in effect for the column. (Inherited from DataGridViewColumn.)
Public propertyInheritedStyleGets the cell style currently applied to the column. (Inherited from DataGridViewColumn.)
Public propertyIsDataBoundGets a value indicating whether the column is bound to a data source. (Inherited from DataGridViewColumn.)
Protected propertyIsRowGets a value indicating whether the band represents a row. (Inherited from DataGridViewBand.)
Public propertyItemsGets the collection of objects used as selections in the combo boxes.
Public propertyMaxDropDownItemsGets or sets the maximum number of items in the drop-down list of the cells in the column.
Public propertyMinimumWidthGets or sets the minimum width, in pixels, of the column. (Inherited from DataGridViewColumn.)
Public propertyNameGets or sets the name of the column. (Inherited from DataGridViewColumn.)
Public propertyReadOnlyGets or sets a value indicating whether the user can edit the column's cells. (Inherited from DataGridViewColumn.)
Public propertyResizableGets or sets a value indicating whether the column is resizable. (Inherited from DataGridViewColumn.)
Public propertySelectedGets or sets a value indicating whether the band is in a selected user interface (UI) state. (Inherited from DataGridViewBand.)
Public propertySiteInfrastructure. Gets or sets the site of the column. (Inherited from DataGridViewColumn.)
Public propertySortedGets or sets a value indicating whether the items in the combo box are sorted.
Public propertySortModeGets or sets the sort mode for the column. (Inherited from DataGridViewColumn.)
Public propertyStateGets the user interface (UI) state of the element. (Inherited from DataGridViewElement.)
Public propertyTagGets or sets the object that contains data to associate with the band. (Inherited from DataGridViewBand.)
Public propertyToolTipTextGets or sets the text used for ToolTips. (Inherited from DataGridViewColumn.)
Public propertyValueMemberGets or sets a string that specifies the property or column from which to get values that correspond to the selections in the drop-down list.
Public propertyValueTypeGets or sets the data type of the values in the column's cells. (Inherited from DataGridViewColumn.)
Public propertyVisibleGets or sets a value indicating whether the column is visible. (Inherited from DataGridViewColumn.)
Public propertyWidthGets or sets the current width of the column. (Inherited from DataGridViewColumn.)
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  NameDescription
Public methodCloneCreates an exact copy of this column. (Overrides DataGridViewColumn.Clone().)
Public methodDispose()Releases all resources used by the DataGridViewBand. (Inherited from DataGridViewBand.)
Protected methodDispose(Boolean)Releases the unmanaged resources used by the DataGridViewBand and optionally releases the managed resources. (Inherited from DataGridViewColumn.)
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodFinalizeReleases the resources associated with the band. (Inherited from DataGridViewBand.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetPreferredWidthCalculates the ideal width of the column based on the specified criteria. (Inherited from DataGridViewColumn.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Protected methodOnDataGridViewChangedCalled when the band is associated with a different DataGridView. (Inherited from DataGridViewBand.)
Protected methodRaiseCellClickRaises the DataGridView.CellClick event. (Inherited from DataGridViewElement.)
Protected methodRaiseCellContentClickRaises the DataGridView.CellContentClick event. (Inherited from DataGridViewElement.)
Protected methodRaiseCellContentDoubleClickRaises the DataGridView.CellContentDoubleClick event. (Inherited from DataGridViewElement.)
Protected methodRaiseCellValueChangedRaises the DataGridView.CellValueChanged event. (Inherited from DataGridViewElement.)
Protected methodRaiseDataErrorRaises the DataGridView.DataError event. (Inherited from DataGridViewElement.)
Protected methodRaiseMouseWheelRaises the Control.MouseWheel event. (Inherited from DataGridViewElement.)
Public methodToStringGets a string that describes the column. (Overrides DataGridViewColumn.ToString().)
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  NameDescription
Public eventDisposedOccurs when the DataGridViewColumn is disposed. (Inherited from DataGridViewColumn.)
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The DataGridViewComboBoxColumn class is a specialized type of DataGridViewColumn used to logically host cells that enable users to select values from a list of choices. A DataGridViewComboBoxColumn has an associated DataGridViewComboBoxCell in every DataGridViewRow that intersects it.

You can populate the cells manually by setting their Value properties. Alternatively, you can bind the column to the data source indicated by the DataGridView.DataSource property. If the DataGridView is bound to a database table, set the column DataPropertyName property to the name of a column in the table. If the DataGridView is bound to a collection of objects, set the DataPropertyName property to the name of an object property.

You can populate the column drop-down list manually by adding values to the Items collection. Alternatively, you can bind the drop-down list to its own data source by setting the column DataSource property. If the values are objects in a collection or records in a database table, you must also set the DisplayMember and ValueMember properties. The DisplayMember property indicates which object property or database column provides the values that are displayed in the drop-down list. The ValueMember property indicates which object property or database column is used to set the cell Value property.

One typical scenario is to bind the DataGridView control to a parent database table and bind the drop-down list to a related child table. For example, you might bind the DataGridView control to an Orders table that contains a ProductID column and set the column DataSource property to a Products table that contains ProductID and ProductName columns. In this case, you would set the column DataPropertyName property to "ProductID" to populate its cell values from the Orders.ProductID column. However, to display the actual product names in the cells and the drop-down list, you would map these values to the Products table by setting the ValueMember property to "ProductID" and the DisplayMember property to "ProductName".

The drop-down list values (or the values indicated by the ValueMember property) must include the actual cell values or the DataGridView control will throw an exception.

Setting the column DataSource, DisplayMember, and ValueMember properties automatically sets the corresponding properties of all cells in the column including the CellTemplate. To override these property values for specific cells, set the column property first, and then set the cell properties.

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.

The default sort mode for this column type is NotSortable.

Notes to Inheritors

When you derive from DataGridViewComboBoxColumn and add new properties to the derived class, be sure to override the Clone method to copy the new properties during cloning operations. You should also call the base class's Clone method so that the properties of the base class are copied to the new cell.

The following code example demonstrates how to use a DataGridViewComboBoxColumn to aid in entering data into the TitleOfCourtesy column.

using System;
using System.Data;
using System.Data.SqlClient;
using System.Windows.Forms;
using System.Collections.Generic;
using System.Drawing;

public class Employees : Form
{
    private DataGridView DataGridView1 = new DataGridView();
    private DataGridView DataGridView2 = new DataGridView();

    [STAThread]
    public static void Main()
    {
        try
        {
            Application.EnableVisualStyles();
            Application.Run(new Employees());
        }
        catch (Exception e)
        {
            MessageBox.Show(e.Message + e.StackTrace);
        }
    }

    public Employees()
    {
        this.Load += new EventHandler(Form1_Load);
    }

    private void Form1_Load(System.Object sender, System.EventArgs e)
    {
        try
        {
            SetUpForm();
            SetUpDataGridView1();
            SetUpDataGridView2();
        }
        catch (SqlException)
        {
            MessageBox.Show("The connection string <"
                + connectionString
                + "> failed to connect.  Modify it "
                + "to connect to a Northwind database accessible to "
                + "your system.",
                "ERROR", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
            Application.Exit();
        }
    }

    private void SetUpForm()
    {
        Size = new Size(800, 600);
        FlowLayoutPanel flowLayout = new FlowLayoutPanel();
        flowLayout.FlowDirection = FlowDirection.TopDown;
        flowLayout.Dock = DockStyle.Fill;
        Controls.Add(flowLayout);
        Text = "DataGridView columns demo";

        flowLayout.Controls.Add(DataGridView1);
        flowLayout.Controls.Add(DataGridView2);
    }

    private void SetUpDataGridView2()
    {
        DataGridView2.Dock = DockStyle.Bottom;
        DataGridView2.TopLeftHeaderCell.Value = "Sales Details";
        DataGridView2.RowHeadersWidthSizeMode = 
            DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders;
    }

    private void SetUpDataGridView1()
    {
        DataGridView1.DataError += new 
            DataGridViewDataErrorEventHandler(DataGridView1_DataError);
        DataGridView1.CellContentClick += new 
            DataGridViewCellEventHandler(DataGridView1_CellContentClick);
        DataGridView1.CellValuePushed += new 
            DataGridViewCellValueEventHandler(DataGridView1_CellValuePushed);
        DataGridView1.CellValueNeeded += new 
            DataGridViewCellValueEventHandler(DataGridView1_CellValueNeeded);

        // Virtual mode is turned on so that the 
        // unbound DataGridViewCheckBoxColumn will 
        // keep its state when the bound columns are 
        // sorted.       
        DataGridView1.VirtualMode = true;
        DataGridView1.AutoSize = true;
        DataGridView1.DataSource = Populate("SELECT * FROM Employees");
        DataGridView1.TopLeftHeaderCell.Value = "Employees";
        DataGridView1.RowHeadersWidthSizeMode = 
            DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders;
        DataGridView1.ColumnHeadersHeightSizeMode = 
            DataGridViewColumnHeadersHeightSizeMode.AutoSize;
        DataGridView1.AutoSizeColumnsMode = 
            DataGridViewAutoSizeColumnsMode.AllCells;
        DataGridView1.AllowUserToAddRows = false;
        DataGridView1.AllowUserToDeleteRows = false;

        // The below autogenerated column is removed so  
        // a DataGridViewComboboxColumn could be used instead.
        DataGridView1.Columns.Remove(ColumnName.TitleOfCourtesy.ToString());
        DataGridView1.Columns.Remove(ColumnName.ReportsTo.ToString());

        AddLinkColumn();
        AddComboBoxColumns();
        AddButtonColumn();
        AddOutOfOfficeColumn();
    }

    private void AddComboBoxColumns()
    {
        DataGridViewComboBoxColumn comboboxColumn;
        comboboxColumn = CreateComboBoxColumn();
        SetAlternateChoicesUsingDataSource(comboboxColumn);
        comboboxColumn.HeaderText = "TitleOfCourtesy (via DataSource property)";
        DataGridView1.Columns.Insert(0, comboboxColumn);

        comboboxColumn = CreateComboBoxColumn();
        SetAlternateChoicesUsingItems(comboboxColumn);
        comboboxColumn.HeaderText = "TitleOfCourtesy (via Items property)";
        // Tack this example column onto the end.
        DataGridView1.Columns.Add(comboboxColumn);
    }

    private void AddLinkColumn()
    {
        DataGridViewLinkColumn links = new DataGridViewLinkColumn();

        links.UseColumnTextForLinkValue = true;
        links.HeaderText = ColumnName.ReportsTo.ToString();
        links.DataPropertyName = ColumnName.ReportsTo.ToString();
        links.ActiveLinkColor = Color.White;
        links.LinkBehavior = LinkBehavior.SystemDefault;
        links.LinkColor = Color.Blue;
        links.TrackVisitedState = true;
        links.VisitedLinkColor = Color.YellowGreen;

        DataGridView1.Columns.Add(links);
    }

    private static void SetAlternateChoicesUsingItems(
        DataGridViewComboBoxColumn comboboxColumn)
    {
        comboboxColumn.Items.AddRange("Mr.", "Ms.", "Mrs.", "Dr.");
    }

    private DataGridViewComboBoxColumn CreateComboBoxColumn()
    {
        DataGridViewComboBoxColumn column =
            new DataGridViewComboBoxColumn();
        {
            column.DataPropertyName = ColumnName.TitleOfCourtesy.ToString();
            column.HeaderText = ColumnName.TitleOfCourtesy.ToString();
            column.DropDownWidth = 160;
            column.Width = 90;
            column.MaxDropDownItems = 3;
            column.FlatStyle = FlatStyle.Flat;
        }
        return column;
    }

    private void SetAlternateChoicesUsingDataSource(DataGridViewComboBoxColumn comboboxColumn)
    {
        {
            comboboxColumn.DataSource = RetrieveAlternativeTitles();
            comboboxColumn.ValueMember = ColumnName.TitleOfCourtesy.ToString();
            comboboxColumn.DisplayMember = comboboxColumn.ValueMember;
        }
    }

    private DataTable RetrieveAlternativeTitles()
    {
        return Populate("SELECT distinct TitleOfCourtesy FROM Employees");
    }

    string connectionString =
        "Integrated Security=SSPI;Persist Security Info=False;" +
        "Initial Catalog=Northwind;Data Source=localhost";

    private DataTable Populate(string sqlCommand)
    {
        SqlConnection northwindConnection = new SqlConnection(connectionString);
        northwindConnection.Open();

        SqlCommand command = new SqlCommand(sqlCommand, northwindConnection);
        SqlDataAdapter adapter = new SqlDataAdapter();
        adapter.SelectCommand = command;

        DataTable table = new DataTable();
        table.Locale = System.Globalization.CultureInfo.InvariantCulture;
        adapter.Fill(table);

        return table;
    }

    // Using an enum provides some abstraction between column index 
    // and column name along with compile time checking, and gives 
    // a handy place to store the column names. 
    enum ColumnName
    {
        EmployeeId,
        LastName,
        FirstName,
        Title,
        TitleOfCourtesy,
        BirthDate,
        HireDate,
        Address,
        City,
        Region,
        PostalCode,
        Country,
        HomePhone,
        Extension,
        Photo,
        Notes,
        ReportsTo,
        PhotoPath,
        OutOfOffice
    };

    private void AddButtonColumn()
    {
        DataGridViewButtonColumn buttons = new DataGridViewButtonColumn();
        {
            buttons.HeaderText = "Sales";
            buttons.Text = "Sales";
            buttons.UseColumnTextForButtonValue = true;
            buttons.AutoSizeMode =
                DataGridViewAutoSizeColumnMode.AllCells;
            buttons.FlatStyle = FlatStyle.Standard;
            buttons.CellTemplate.Style.BackColor = Color.Honeydew;
            buttons.DisplayIndex = 0;
        }

        DataGridView1.Columns.Add(buttons);

    }

    private void AddOutOfOfficeColumn()
    {
        DataGridViewCheckBoxColumn column = new DataGridViewCheckBoxColumn();
        {
            column.HeaderText = ColumnName.OutOfOffice.ToString();
            column.Name = ColumnName.OutOfOffice.ToString();
            column.AutoSizeMode = 
                DataGridViewAutoSizeColumnMode.DisplayedCells;
            column.FlatStyle = FlatStyle.Standard;
            column.ThreeState = true;
            column.CellTemplate = new DataGridViewCheckBoxCell();
            column.CellTemplate.Style.BackColor = Color.Beige;
        }

        DataGridView1.Columns.Insert(0, column);
    }

    private void PopulateSales(DataGridViewCellEventArgs buttonClick)
    {

        string employeeId = DataGridView1.Rows[buttonClick.RowIndex]
            .Cells[ColumnName.EmployeeId.ToString()].Value.ToString();
        DataGridView2.DataSource = Populate("SELECT * FROM Orders WHERE EmployeeId = " + employeeId);
    }

    #region "SQL Error handling" 
    private void DataGridView1_DataError(object sender, DataGridViewDataErrorEventArgs anError)
    {

        MessageBox.Show("Error happened " + anError.Context.ToString());

        if (anError.Context == DataGridViewDataErrorContexts.Commit)
        {
            MessageBox.Show("Commit error");
        }
        if (anError.Context == DataGridViewDataErrorContexts.CurrentCellChange)
        {
            MessageBox.Show("Cell change");
        }
        if (anError.Context == DataGridViewDataErrorContexts.Parsing)
        {
            MessageBox.Show("parsing error");
        }
        if (anError.Context == DataGridViewDataErrorContexts.LeaveControl)
        {
            MessageBox.Show("leave control error");
        }

        if ((anError.Exception) is ConstraintException)
        {
            DataGridView view = (DataGridView)sender;
            view.Rows[anError.RowIndex].ErrorText = "an error";
            view.Rows[anError.RowIndex].Cells[anError.ColumnIndex].ErrorText = "an error";

            anError.ThrowException = false;
        }
    }
    #endregion

    private void DataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
    {

        if (IsANonHeaderLinkCell(e))
        {
            MoveToLinked(e);
        }
        else if (IsANonHeaderButtonCell(e))
        {
            PopulateSales(e);
        }
    }

    private void MoveToLinked(DataGridViewCellEventArgs e)
    {
        string employeeId;
        object value = DataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value;
        if (value is DBNull) { return; }

        employeeId = value.ToString();
        DataGridViewCell boss = RetrieveSuperiorsLastNameCell(employeeId);
        if (boss != null)
        {
            DataGridView1.CurrentCell = boss;
        }
    }

    private bool IsANonHeaderLinkCell(DataGridViewCellEventArgs cellEvent)
    {
        if (DataGridView1.Columns[cellEvent.ColumnIndex] is
            DataGridViewLinkColumn &&
            cellEvent.RowIndex != -1)
        { return true; }
        else { return false; }
    }

    private bool IsANonHeaderButtonCell(DataGridViewCellEventArgs cellEvent)
    {
        if (DataGridView1.Columns[cellEvent.ColumnIndex] is
            DataGridViewButtonColumn &&
            cellEvent.RowIndex != -1)
        { return true; }
        else { return (false); }
    }

    private DataGridViewCell RetrieveSuperiorsLastNameCell(string employeeId)
    {

        foreach (DataGridViewRow row in DataGridView1.Rows)
        {
            if (row.IsNewRow) { return null; }
            if (row.Cells[ColumnName.EmployeeId.ToString()].Value.ToString().Equals(employeeId))
            {
                return row.Cells[ColumnName.LastName.ToString()];
            }
        }
        return null;
    }

    #region "checkbox state"
    Dictionary<string, bool> inOffice = new Dictionary<string, bool>();
    private void DataGridView1_CellValuePushed(object sender,
        DataGridViewCellValueEventArgs e)
    {
        if (IsCheckBoxColumn(e.ColumnIndex))
        {
            string employeeId = GetKey(e);
            if (!inOffice.ContainsKey(employeeId))
            {
                inOffice.Add(employeeId, (Boolean)e.Value);
            }
            else
            {
                inOffice[employeeId] = (Boolean)e.Value;
            }
        }
    }

    private string GetKey(DataGridViewCellValueEventArgs cell)
    {
        return DataGridView1.Rows[cell.RowIndex].
            Cells[ColumnName.EmployeeId.ToString()].Value.ToString();
    }

    private void DataGridView1_CellValueNeeded(object sender,
        DataGridViewCellValueEventArgs e)
    {

        if (IsCheckBoxColumn(e.ColumnIndex))
        {
            string employeeId = GetKey(e);
            if (!inOffice.ContainsKey(employeeId))
            {
                bool defaultValue = false;
                inOffice.Add(employeeId, defaultValue);
            }

            e.Value = inOffice[employeeId];
        }
    }

    private bool IsCheckBoxColumn(int columnIndex)
    {
        DataGridViewColumn outOfOfficeColumn =
            DataGridView1.Columns[ColumnName.OutOfOffice.ToString()];
        return (DataGridView1.Columns[columnIndex] == outOfOfficeColumn);
    }
    #endregion
}

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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