Re: Populating combobox with values from Table using C# - C# Discussion Boards

Yusuf4-Mar-09 9:23

4-Mar-09 9:23

I have seen many that give examples, but they wont give you real working one.

See here[^] and here[^] for code examples

Yusuf

Re: System.Net.Mail setup

dptalt4-Mar-09 10:01

dptalt

4-Mar-09 10:01

The code file in the second link is very cool. Thanks!

Re: System.Net.Mail setup

Yusuf4-Mar-09 10:14

Yusuf

4-Mar-09 10:14

use it responsibly.

Yusuf

Re: System.Net.Mail setup

Dave Kreskowiak4-Mar-09 9:51

Dave Kreskowiak

4-Mar-09 9:51

System.Net.Mail is not a class, but is a namespace.

Documentation...[^]

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

Populating combobox with values from Table using C#

haroon19804-Mar-09 8:05

haroon1980

4-Mar-09 8:05

Hi,

I have following function below but is not populating values from the table product?

private void comboBox3_SelectedIndexChanged(object sender, EventArgs e)
        {
            try
            {
 
                database = new OleDbConnection(connectionString);
 
                // Create a command object and then a query which accepts a papameter
                System.Data.OleDb.OleDbCommand cmd = new System.Data.OleDb.OleDbCommand("Select * from Products", database);
                database.Open();
                System.Data.OleDb.OleDbDataReader dr;
                dr=cmd.ExecuteReader();
 
                while (dr.Read())
                {
                    //comboBox3.Items.AddRange(new object[] { dr[1].ToString() });  //Change the index according to the values you want to populate in the combobox.
                    comboBox3.Items.Add(dr["ProductName"]);
 
                }
            }
                catch (Exception ex)
            {
 
                MessageBox.Show(ex.Message);
                return;
            }
                
               
               }

regards,

Re: Populating combobox with values from Table using C# [modified]

Jimmanuel4-Mar-09 8:41

Jimmanuel

4-Mar-09 8:41

- you probably want to clear out the old values from the combo box before you populate it with new data
- don't forget to close dr and database after you're finished using them otherwise you'll leak resources
- what happens when you step through this in the debugger? does your while loop properly iterate through all the rows in the DB?
- if the only column you're using from the DB table is ProductName then doing a Select * is rather inefficient.
- just for my own curiosity, why are you doing this in the SelectedIndexChanged event handler for the combo box?

Last modified: after originally posted -- grammar correction

Re: Populating combobox with values from Table using C#

haroon19804-Mar-09 9:18

haroon1980

4-Mar-09 9:18

Hi Jimmanuel,
...What else method or way u recommend instead of SelectedIndexChanged ? can u pls gimme example?
... I have 3 fields in that table so why it is inefficient?

i have changed code and following is here: to include dr.close method..

 private void comboBox3_SelectedIndexChanged(object sender, EventArgs e)
        {
            try
            {

                database = new OleDbConnection(connectionString);

                // Create a command object and then a query which accepts a papameter
                System.Data.OleDb.OleDbCommand cmd = new System.Data.OleDb.OleDbCommand("Select distinct ProductName from Products", database);
                database.Open();
                System.Data.OleDb.OleDbDataReader dr;
                dr = cmd.ExecuteReader();

                while (dr.Read())
                {
                    //comboBox3.Items.AddRange(new object[] { dr[1].ToString() });  //Change the index according to the values you want to populate in the combobox.
                    comboBox3.Items.AddRange(new Object[] { dr[1].ToString() });
                    
                }
                dr.Close();
            }
            catch (Exception ex)
            {

                MessageBox.Show(ex.Message);
                return;
            }
}

please help

Re: Populating combobox with values from Table using C#

Jimmanuel4-Mar-09 9:44

Jimmanuel

4-Mar-09 9:44

How often is the DB Table going to change? If it doesn't change or rarely changes then you really only need to populate the combo box values once - when the form loads. If it does change frequently then there are lots of good ways to keep the combo box up to date. You could use a timer to reload the values every so often, put a button on the form that allows the user to refresh whenever they want or work out some way of receiving a notification any time that the table changes.

database.Close() is just as important. That closes the connection to the DB, otherwise it gets orphaned. A using[^] statement would be helpful in making sure that everything gets cleaned up whether an exception is thrown or not.

Say your table has 10 rows; that means that all you want from it is 10 product names but a select * statement is giving you back the 10 product names plus 20 other values that you aren't using. That's 3 times as much network traffic as you actually need. It might not be a big deal now but what if there were 10,000 rows? What if later on the table changes and more columns get added? For each column that's added that's more unnecessary traffic between your app and your DB and more time and memory required to handle your select. Select distinct ProductName is the way to go here. In fact, I can't recall a time that I've ever used select *.

Re: Populating combobox with values from Table using C#

Yusuf4-Mar-09 9:26

Yusuf

4-Mar-09 9:26

why are you populating comboBox3 from db when something got selected on the same combobox?

You know showing any other thing except populating your combobox. You need to do this only once or when ever the data changes.

Yusuf

Re: Populating combobox with values from Table using C#

haroon19804-Mar-09 10:54

haroon1980

4-Mar-09 10:54

thanks Yusuf, i just want to see the product names in this comboBox thats all..and which will come from Products Table...

regards,

Confused | :confused:

C# Referencing Cell on DataGrid

Wheels0124-Mar-09 6:06

Wheels012

4-Mar-09 6:06

Good afternoon.

I am trying to reference the cell on a datagrid.

The Description column is hidden, but I want the description to populate a text box when the user clicks on a specific row.

I have the following so far:
rtxtDescription.Text = DataGridView1.Rows[index].Cells[2].Value.ToString();

The column is 2 and the row would depended on which row is selected.

I am using Visual Studio 2008.

Any suggestions?

WHEELS

Re: C# Referencing Cell on DataGrid

dan!sh 4-Mar-09 6:08

dan!sh

4-Mar-09 6:08

CellClick event?

Time is the best teacher; unfortunately it kills all of its students.

जय हिंद

Re: C# Referencing Cell on DataGrid

Wheels0124-Mar-09 6:40

Wheels012

4-Mar-09 6:40

It is actually in a method:

public void PopulateDataGrid()
{
ds = new DataSet();
ds = d.FillDataGrid(this.cboDepartment.SelectedValue.ToString(), this.txtAcronym.Text);
DataGridView1.Columns.Clear();
if (ds != null && ds.Tables.Count != 0)
{
BindingSource bs = new BindingSource();
bs.DataSource = ds;
bs.DataMember = ds.Tables[0].TableName;
DataGridView1.DataSource = bs;
//return;
}
foreach (DataGridViewColumn col in DataGridView1.Columns)
{
if (col.HeaderText == constrDescrColumn) { col.Visible = false; }
}
//MessageBox.Show(DataGridView1.CurrentRow.Cells.IndexOf(.ToString());
int index = 0;
rtxtDescription.Text = DataGridView1.Rows[index].Cells[2].Value.ToString();

}

Re: C# Referencing Cell on DataGrid

led mike4-Mar-09 7:13

led mike

4-Mar-09 7:13

Wheels012 wrote:
It is actually in a method:

In your first post you asked for suggestions and the reply was "CellClick event"

Now I could be wrong, but if I am correct it appears you have completely missed the point.

Re: C# Referencing Cell on DataGrid

Wheels0124-Mar-09 7:19

Wheels012

4-Mar-09 7:19

Good afernoon led mike.

I am very new to C# (huge VBA background).

My first hurdle is to populate the text box with the discription from the first cell from the description column.

Secondly I need to add this to the click event once a user changes from record to record.

WHEELS

Re: C# Referencing Cell on DataGrid

Samuel Cherinet4-Mar-09 19:54

Samuel Cherinet

4-Mar-09 19:54

you can use the indexer of the datagridveiw to directly find the cell you are looking for and also use the property "FormattedValue" to get the displayed text of the cell

str=dgrid[colIndex,rowIndex].FormattedValue.ToString();

I have to remind you,If you already don't know, that an empty cell means most of the time null, that is like a fuel to run time error, so be aware of that.
- try using the "RowEnter" event and access the selected row by the "DataGridViewCellEventArgs" in the event handler.

best of luck

Re: C# Referencing Cell on DataGrid

Wheels0125-Mar-09 1:22

Wheels012

5-Mar-09 1:22

Thank you everyone.

This is a great forum.

WHEELS

icons in buttons with flatstyle.System

mirko864-Mar-09 5:43

mirko86

4-Mar-09 5:43

Good day people i have a little problem i hope you guys can help me

i have a windows form with some buttons and their flatstyle is set to Flatstyle.System, i used to have it set to
Flatstyle.Standard so i could put icons in them, but since i changed it to Flatstyle.System i cant put icons in them

is there any way i can put icons in buttons with FlatStyle.System?

thanks a lot in advance

Re: icons in buttons with flatstyle.System

Xmen Real 4-Mar-09 6:05

Xmen Real

4-Mar-09 6:05

Well, it always works on mine. I used Image property.

TVMU^P[[IGIOQHG^JSH`A#@`RFJ\c^JPL>;"[,*/|+&WLEZGc`AFXc!L
%^]*IRXD#@GKCQ`R\^SF_WcHbORY87֦ʻ6ϣN8ȤBcRAV\Z^&SU~%CSWQ@#2
W_AD`EPABIKRDFVS)EVLQK)JKSQXUFYK[M`UKs*$GwU#(QDXBER@CBN%
Rs0~53%eYrd8mt^7Z6]iTF+(EWfJ9zaK-iTV.C\y<pjxsg-b$f4ia>
--------------------------------------------------------
128 bit encrypted signature, crack if you can

ComboBox in DataGridview

rafaelht31084-Mar-09 4:31

rafaelht3108

4-Mar-09 4:31

Help me, I have Combobox in Datagriview i need bind combobox, but my code no bind it.

DataSet ds = new DataSet();
ds = neP.NE_Cargar_Procedimientos_Costos();
DataGridViewComboBoxColumn cbox = new DataGridViewComboBoxColumn();

foreach (DataGridViewRow row in dgvCostos.Rows)
{
if (dgvCostos.Columns[2].Name == "storedproc")
{
cbox.DataSource = ds.Tables[0].DefaultView;
cbox.DisplayMember = "name";
cbox.ValueMember = "id";
}
}

Help me Frown | :(

Re: ComboBox in DataGridview

Xmen Real 4-Mar-09 4:54

Xmen Real

4-Mar-09 4:54

As far as I understood your code, you're trying to bind every Row's Combobox. But the fact is, its only one combobox associated with the column. So if you bind the combobox it will be same in every row.

Re: ComboBox in DataGridview

rafaelht31084-Mar-09 5:07

rafaelht3108

4-Mar-09 5:07

as it could then bind the combobox, i need bind all combobox, thank you Xmen

water marking

rohan40404-Mar-09 4:25

rohan4040

4-Mar-09 4:25

how can we apply self embedding water marking technique to images using vb.net or c#.net technique

Re: water marking

Xmen Real 4-Mar-09 4:35

Xmen Real

4-Mar-09 4:35

first there are 2 buttons on the right-bottom in every message you post. One called 'Edit' and the second one 'Delete'. So if by mistake you posted 2 same messages you can use 'Delete' and to edit the message you can use 'Edit'. Simple as usual Wink | ;)

As well as, here[^] is something for you

water marking

rohan40404-Mar-09 4:23

rohan4040

4-Mar-09 4:23

how can i apply cosine transformation to an image using c#.net

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.