Using New ComboBox ActiveX With C#


When I create a project for using a DataGrid with a ComboBox, I hope to get a resizable ComboBox to set its height as the height of the DataGrid cell. This is my attempt to create a resizable ComboBox ActiveX, now I can change its Height. Some programmers use a Form, ListBox, TextBox and a Button to create a ComboBox, but I am using a Panel, ComboBox, TextBox and a Button to create my ActiveX. Using a Panel to hide the upper part of the ComboBox and using this Panel as the container for the TextBox and Button.


About the Project of my ActiveX:

  • Name of the Project is: MKCombo
  • Name of UserControl is: KCombo
  • Name of Panel is: ComboHide
  • Name of ComboBox is: ComboCtrl
  • Name of TextBox is: ComboText
  • Name of Button is: ComboButton

After you expand the files:, you can open "SizableCombo" solution to read the code of my ActiveX in the "MKCombo" project and read the code to test the ActiveX in the "SizableCombo" project.

I try to use "DataSource" to bind my ActiveX with data but I can't, so then I use another idea.

My ActiveX has:

  • Event: cmbSelectedChanged for SelectedIndexChanged event.
  • Property: cmbBorderStyle for BorderStyle property.
  • Property: cmbSelectedIndex for SelectedIndex property.
  • Property: cmbSelectedItem for SelectedItem property.
  • Property: cmbText for Text property.
  • Property: cmbItemsCount for Items.Count property.
  • Method: cmbAddItem for Items.Add method.
  • Method: cmbClear for Items.Clear method.

About the Code

Code to bind the ActiveX with data:

public void cmbBindData(string cmbSql, OleDbConnection cmbCnn, string cmbField)
    if (cmbCnn.State == ConnectionState.Open)
    OleDbCommand cmdReader = new OleDbCommand(cmbSql, cmbCnn);
    OleDbDataReader datRdr = cmdReader.ExecuteReader();
    while (datRdr.Read())
    ComboCtrl.SelectedIndex = 0;


When the test project is executed, please resize any row to see how the ComboBox changes its height.

I hope this article is useful. If you have any idea, please tell me.

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