how to fill a combobox with a class

adrian salas

Hi, I am filling a combobox with the code below: private void frmCrearCooperativa_Load(object sender, EventArgs e) { string nacionalidad = "select * from cs_nacionalidad"; try { //open connection bdConex.OpenConnection(); //create command and assign the query and connection from the constructor MySqlDataAdapter da = new MySqlDataAdapter(nacionalidad, bdConex.conn); //create dataset DataSet ds = new DataSet(); // filling dataset da.Fill(ds, "cs_nacionalidad"); //dataset values cboNacionalidad.DataSource = ds.Tables["cs_nacionalidad"]; cboNacionalidad.DisplayMember = "nm_nacionalidad"; cboNacionalidad.ValueMember = "cd_nacionalidad"; //close connection bdConex.CloseConnection(); } catch (Exception ex) { MessageBox.Show(ex.Message); } how do I can do a class that fills the combobox with this code? because I have to write it down in all forms. thanks.

gavindon

I dont have your answer but, If you would like the guys who know more than me to answer you might want to edit your post and put the code in a code block

code here

by using pre tags to make it easier to read.

Programming is a race between programmers trying to build bigger and better idiot proof programs, and the universe trying to build bigger and better idiots, so far... the universe is winning.

sanforjackass

you only need to pass dataset object

EASY COME EASY GO

walterhevedeich

You can just create a method that accepts a combobox as parameter. and then inside your method, just do the usual setting of the datasource to your combobox, just like what you are doing in your code. Im not sure though if your data source for your combo boxes will be the same. If it isn't, you might want to add parameters for your datasource, displaymember, and valuemember to your method.

Ignorance of the ability brings disability.

Lukasz Nowakowski

You can create a class, that derives from ComboBox, and there you do

protected override void OnLoad(EventArgs e)
{
string nacionalidad = "select * from cs_nacionalidad";
try
{
//open connection
bdConex.OpenConnection();
//create command and assign the query and connection from the constructor
MySqlDataAdapter da = new MySqlDataAdapter(nacionalidad, bdConex.conn);
//create dataset
DataSet ds = new DataSet();
// filling dataset
da.Fill(ds, "cs_nacionalidad");
//dataset values
cboNacionalidad.DataSource = ds.Tables["cs_nacionalidad"];
cboNacionalidad.DisplayMember = "nm_nacionalidad";
cboNacionalidad.ValueMember = "cd_nacionalidad";
//close connection
bdConex.CloseConnection();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}

And then use this class, where you want ComboBox to contain this data.

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minnie mouse

I think that the answer that you are looking for is that you must add anther class to your project, create a method within that class using your curent code. You then re use this wherever you like by adding a reference to the new class at the top of each form. have a look at what refactoring does. Instances of the class can then be created and its methods etc can be used. Make sense ?

adrian salas

how do I call the class with the combobox as a parameter? Thanks

Lukasz Nowakowski

You don't. You create class:

public class NationSelector : ComboBox
{
protected override void OnLoad(EventArgs e)
{
string nacionalidad = "select * from cs_nacionalidad";
try
{
//open connection
bdConex.OpenConnection();
//create command and assign the query and connection from the constructor
MySqlDataAdapter da = new MySqlDataAdapter(nacionalidad, bdConex.conn);
//create dataset
DataSet ds = new DataSet();
// filling dataset
da.Fill(ds, "cs_nacionalidad");
//dataset values
cboNacionalidad.DataSource = ds.Tables["cs_nacionalidad"];
cboNacionalidad.DisplayMember = "nm_nacionalidad";
cboNacionalidad.ValueMember = "cd_nacionalidad";
//close connection
bdConex.CloseConnection();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}

And then, when you edit your aspx (or ascx), in the toolbox you should see "NationSelector". And you just drag this control on the designer.

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adrian salas

Hi, I did it as you told me: protected override void OnLoad(object sender, EventArgs e) { BDconexion bdConex = new BDconexion(); string nacionalidad = "select * from cs_nacionalidad"; try { //open connection bdConex.OpenConnection(); //create command and assign the query and connection from the constructor MySqlDataAdapter da = new MySqlDataAdapter(nacionalidad, bdConex.conn); //create dataset DataSet ds = new DataSet(); // filling dataset da.Fill(ds, "cs_nacionalidad"); //dataset values NationSelector1.DataSource = ds.Tables["cs_nacionalidad"]; NationSelector1.DisplayMember = "nm_nacionalidad"; NationSelector1.ValueMember = "cd_nacionalidad"; //close connection bdConex.CloseConnection(); } catch (Exception ex) { MessageBox.Show(ex.Message); } But I am having problem with these lines: NationSelector1.DataSource = ds.Tables["cs_nacionalidad"]; NationSelector1.DisplayMember = "nm_nacionalidad"; NationSelector1.ValueMember = "cd_nacionalidad"; what is the name that I should write instead of NationSelector1? thanks.

Lukasz Nowakowski

You should use this. And additionally you should notice, that OnLoad method should have only one argument: EventArgs e

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adrian salas

I did it and there is not error messages, but what I need to do to see the NationSelector combobox in the toolbox? because I compile the code and It does not appear. Thanks.