How Can I Add Items Of Combobox By Selcting Another Combobox's item If Both Combobox Are In Datagridview Of C#

Question

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I have DataGridView which contains two ComboBox columns. I want that The second ComboBox will be filled with data depending on the selected value from first ComboBox.

Below is my code.

Thank you

-Tushar

C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace t1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            logicload(2, 2);
        }
        public void logicload(int row, int col)
        {

            dataGridView1.EditMode = DataGridViewEditMode.EditOnEnter;
            for (int i = 1; i <= col; i++)
            {
                dataGridView1.Columns.Add("Col" + i, "Stage" + i);
            }

            dataGridView1.Rows.Add(row);

            //make row 1 at all columns into combobox cell.
            dataGridView1.Rows[0].Cells[1] = new DataGridViewComboBoxCell();
            dataGridView1.Rows[1].Cells[1] = new DataGridViewComboBoxCell();
            dataGridView1.Rows[0].Cells[0].Value = "Country";
            dataGridView1.Rows[1].Cells[0].Value = "City";

            loadComboboxesSampleItems();
        }
        DataGridViewComboBoxCell CellColumn1, CellColumn2;
        private void loadComboboxesSampleItems()
        {

            CellColumn1 = (DataGridViewComboBoxCell)this.dataGridView1.Rows[0].Cells[1];
             CellColumn2 = (DataGridViewComboBoxCell)this.dataGridView1.Rows[1].Cells[1];
            var list1 = new List<string>() { "IND", "PAK", "AUS", "USA" };
           // var list2 = new List<string>() { "AGRA", "DEHLI", "KANPUR" };
            var list3 = new List<string>() { "MOhali" };

            CellColumn1.DataSource = list1;// CellColumn2.DataSource = list2;

        }

        private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
        {
            ComboBox combo = e.Control as ComboBox;
            if (combo != null)
            {
                combo.SelectedIndexChanged -= new EventHandler(ComboBox_SelectedIndexChanged);
                combo.SelectedIndexChanged += new EventHandler(ComboBox_SelectedIndexChanged);
            }


        }
        private void ComboBox_SelectedIndexChanged(object sender, EventArgs e)
        {
             var list2 = new List<string>() { "AGRA", "DEHLI", "KANPUR" };
            if (CellColumn1.Selected.Equals(true))
            {
                ComboBox cb = (ComboBox)sender;
                string item = cb.Text;
                if (item != null)
                {
                    if (cb.SelectedIndex.Equals(0))
                    {
                        //MessageBox.Show(item);
                        CellColumn2.DataSource = list2;

                    }
                }
            }
           
        }
    }
}

Posted 21-May-14 22:31pm

TusharZoo

Updated 22-May-14 2:43am

v3

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Comments

Richard MacCutchan 22-May-14 4:34am

OK, so what is your question?

TusharZoo 22-May-14 5:27am

how to fill the items of a combobox by selecting the item of another combobox when both combobox are on datagridview c#

suppose we have two combobox one have country name and other have city name

when we select one country name the cities of those country should show on another combobox

Richard MacCutchan 22-May-14 5:36am

OK, so when the item in the first combobox is selected (i.e. in your selection event) you need to populate the second with the items in question. What exactly is your problem?

TusharZoo 22-May-14 6:00am

Actually i am new in c# and i want the simple code for it
(the two combobox should in datagridview (DataGridviewComboBoxCell) and when the item in the first combobox is selected i need to populate the second combobox with items )

Richard MacCutchan 22-May-14 6:07am

You already have the code that adds your list of countries to the first ComboBox. Add an event handler to that which will read the selected item, and use that to add the appropriate city list to the second CombBox.

TusharZoo 22-May-14 6:19am

Actually i tried this several times, but has still failed
please give me the code for that

please help me on this

Richard MacCutchan 22-May-14 6:37am

When you create your ComboBox you need to add an event handler for it, something like:


DataGridViewComboBoxCell cbCountry = new DataGridViewComboBoxCell();
dataGridView1.Rows[0].Cells[1] = cbCountry;
cbCountry.SelectedIndexChanged += new System.EventHandler(cbCountry_SelectedIndexChanged);

Change the name of your event handler to match this name (cbCountry_SelectedIndexChanged). Now add the code inside the handler to check the selected index, use that to identify the country, and then add a list of cities to the second combo for that country.

Richard MacCutchan 22-May-14 7:59am

Please don't dump your code in a reply here, edit your question and put it there so it is properly formatted and readable by everyone.

TusharZoo 22-May-14 8:47am

OK now i have update my question

please give me the appropriate and simple code for that
please help me on this i really need it..

joshrduncan2012 22-May-14 9:12am

No one will provide you a ready made code segment. This is about getting help with code that is already written.

TusharZoo 22-May-14 9:20am

thanks for the suggestion

but i want to know only 2 or 3 missing lines from my source code

Richard MacCutchan 22-May-14 10:32am

You seem to be quite confused about object references and events. I would suggest going back to your reference guide and studying it a bit more.

TusharZoo 22-May-14 12:41pm

thanks for the suggestion

but if you have any example code for that problem then please give me

Richard MacCutchan 22-May-14 13:01pm

I also owe you an apology. I have been trying to produce a simple sample of code to solve your problem, and must admit defeat. Using DataGridViewComboBoxCells in this way is not the same as ordinary ComboBoxes. I have also tried searching for samples in Google but could not find anything that shows how to do it.

TusharZoo 22-May-14 13:18pm

OK if you will find the solution please give me

i really need it..

Richard MacCutchan 22-May-14 13:20pm

Please read my previous message again. The issue does not have a solution that I could find; you will have to research it further for yourself.

V. 22-May-14 5:51am

Don´t post your question twice. It´s considered rude...

TusharZoo 22-May-14 6:08am

ok next time i will remember this

thanks for the suggestion

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gggustafson · Accepted Answer · 2014-05-22T12:28:00

Your for statement

for (int i = 1; i <= col; i++)

uses an unexpected initial value and an unexpected condition test. I would have expected

for ( int i = 0; ( i < col ); i++).

In C#, arrays indices start at 0.

The fragment

"Col" + i, "Stage" + i

is a sign of lazy programming. "i" is not a string and should not be used that way. You should have used

"Col" + i.ToString ( ), "Stage" + i.ToString ( )

CellColumn1.Selected is a boolean. It returns true or false. So your if statement

if ( CellColumn1.Selected.Equals ( true ) )

should read

if ( CellColumn1.Selected )

Your if statement

if ( item != null )

should read

if ( !String.IsNullOrEmpty ( item ) )

Your if statement

if ( combo_box.SelectedIndex.Equals ( 0 ) )

should read

if ( combo_box.SelectedIndex == 0 )

You did not include data for the chosen country

Working example follows.

C#

using System;
using System.Collections.Generic;
using System.Windows.Forms;

namespace DataGridViewComboBoxes
    {

    // *************************************************** class Form1

    public partial class Form1 : Form
        {

        // *************************************** enums and constants

        enum ControlTypes
            {
            COMBO,
            TEXT
            }

        const int                   CITIES_ROW = 1;
        const int                   CITIES_CELL = 1;
        const int                   COUNTRIES_ROW = 0;
        const int                   COUNTRIES_CELL = 1;

        const int                   NUMBER_COLUMNS = 2;
        const int                   NUMBER_ROWS = 2;

        // ************************************************* variables

        List < string >             Australian_cities = 
                                        new List < string > ( ) { 
                                            "Sydney", 
                                            "Melbourne", 
                                            "Brisbane", 
                                            "Perth", 
                                            "Adelaide" };
        DataGridViewComboBoxCell    countries_cell;
        DataGridViewComboBoxCell    cities_cell;
        List < string >             cities;
        List < string >             Indian_cities = 
                                        new List < string > ( ) { 
                                            "Mumbai", 
                                            "Delhi", 
                                            "Bangalore", 
                                            "Karnataka", 
                                            "Hyderabad" };
        List < string >             Pakistani_cities = 
                                        new List < string > ( ) { 
                                            "Karachi", 
                                            "Lahore", 
                                            "Faisalabad", 
                                            "Rawalpindi", 
                                            "Punjab" };
         List < string >             USA_cities = 
                                        new List < string > ( ) { 
                                            "New York", 
                                            "Los Angeles", 
                                            "Chicago", 
                                            "Houston", 
                                            "Philadelphia" };
        List < string >             countries = 
                                        new List < string > ( ) { 
                                            "IND", 
                                            "PAK", 
                                            "AUS", 
                                            "USA" };

        // ***************************************************** Form1

        public Form1 ( )
            {
            InitializeComponent ( );

            initialize_datagridview ( NUMBER_ROWS, NUMBER_COLUMNS );
            load_sample_data ( );

            dataGridView1.DataError += 
                new DataGridViewDataErrorEventHandler ( 
                    dataGridView1_DataError );
            }

        // *********************************** dataGridView1_DataError

        void dataGridView1_DataError ( 
                                object                         sender, 
                                DataGridViewDataErrorEventArgs e )
            {

            }

        // *********************************** initialize_datagridview

        void initialize_datagridview ( int rows, 
                                       int columns )
            {

            dataGridView1.EditMode = DataGridViewEditMode.EditOnEnter;

            for ( int i = 0; ( i < columns ); i++ )
                {
                string i_plus_one = ( i + 1 ).ToString ( );

                dataGridView1.Columns.Add ( "Col" + i_plus_one, 
                                            "Stage" + i_plus_one );
                }

            dataGridView1.Rows.Add ( rows );
                                        // make first row columns into 
                                        // DataGridViewComboBoxCell
            dataGridView1.Rows [ 0 ].Cells [ 1 ] = 
                                    new DataGridViewComboBoxCell ( );
            dataGridView1.Rows [ 1 ].Cells [ 1 ] = 
                                    new DataGridViewComboBoxCell ( );

            dataGridView1.Rows [ 0 ].Cells [ 0 ].Value = "Country";
            dataGridView1.Rows [ 1 ].Cells [ 0 ].Value = "City";

            dataGridView1.EditingControlShowing +=
                new DataGridViewEditingControlShowingEventHandler (
                    dataGridView1_EditingControlShowing );
            }

        // ****************************************** load_sample_data

        private void load_sample_data ( )
            {

            countries_cell = ( DataGridViewComboBoxCell ) 
                                dataGridView1.Rows [ COUNTRIES_ROW ].
                                              Cells [ COUNTRIES_CELL ];
            cities_cell = ( DataGridViewComboBoxCell ) 
                                dataGridView1.Rows [ CITIES_ROW ].
                                              Cells [ CITIES_CELL ];
            countries_cell.DataSource = null;
            countries_cell.DataSource = countries;
            }

        // *********************** dataGridView1_EditingControlShowing

        void dataGridView1_EditingControlShowing ( 
                    object                                     sender, 
                    DataGridViewEditingControlShowingEventArgs e )
            {
            ControlTypes    control_type;
            Object          editing_control;

            try
                {
                editing_control = 
                    ( DataGridViewTextBoxEditingControl ) e.Control;
                control_type = ControlTypes.TEXT;
                }
            catch
                {
                editing_control = 
                    ( DataGridViewComboBoxEditingControl ) e.Control;
                control_type = ControlTypes.COMBO;
                }

            if ( control_type == ControlTypes.COMBO )
                {
                ComboBox  combo_box = ( ComboBox ) editing_control;

                if ( combo_box != null )
                    {
                    combo_box.TextChanged -= 
                        new EventHandler ( 
                            editingcontrol_TextChanged );
                    combo_box.TextChanged += 
                        new EventHandler ( 
                            editingcontrol_TextChanged );
                    }
                }
            }

        // ******************************** editingcontrol_TextChanged

        void editingcontrol_TextChanged ( object    sender, 
                                             EventArgs e )
            {

            if ( countries_cell.Selected )
                {
                ComboBox    combo_box = ( ComboBox ) sender;
                string      text = combo_box.Text;

                if ( !String.IsNullOrEmpty ( text ) )
                    {
                    switch ( text )
                        {
                        case "IND":
                            cities = Indian_cities;
                            break;

                        case "PAK":
                            cities = Pakistani_cities;
                            break;

                        case "AUS":
                            cities = Australian_cities;
                            break;

                        case "USA":
                            cities = USA_cities;
                            break;

                        default:
                            throw new ApplicationException ( 
                                "Unrecognized country" );
                        }
                                        // avoid DataError by rebuild
                                        // of cities_cell
                    cities_cell.Dispose ( );
                    cities_cell = ( DataGridViewComboBoxCell ) 
                                        dataGridView1.
                                            Rows [ CITIES_ROW ].
                                            Cells [ CITIES_CELL ];
                    combo_box.TextChanged -= 
                        new EventHandler ( 
                            editingcontrol_TextChanged );
                    combo_box.TextChanged += 
                        new EventHandler ( 
                            editingcontrol_TextChanged );

                    cities_cell.DataSource = null;
                    cities_cell.DataSource = cities;
                    }
                }
            }

        } // class Form1

    } // namespace DataGridViewComboBoxes

Hope that helps.