Bind a dataset to a combo box in C#

By: Rajesh P.S.

The DataSet is a memory-resident representation of data that offers a consistent relational programming model, irrespective of the data source. It provides a structured way to store and manage data, including tables, relationships, and constraints.

The SqlDataAdapter object allows us to populate DataTables within a DataSet. It facilitates retrieving data from a data source and populating the DataTables using methods like Fill(), providing seamless integration of data into the DataSet.

Bind data source to ComboBox

The ComboBox control allows the user to select an option from a list. We can populate a ComboBox from the values in a DataSet, providing a user-friendly interface for selecting options. This is often done by binding the ComboBox to the DataSet's values.

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comboBox1.DataSource = ds.Tables[0]; comboBox1.ValueMember = "au_id"; comboBox1.DisplayMember = "au_lname";

Select Item from ComboBox

comboBox1.SelectedValue

The following C# program retrieve the values from database and store it in a dataset and later bind to a combobox.

using System; using System.Data; using System.Data.SqlClient; using System.Windows.Forms; namespace WindowsFormsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { string connetionString = null; SqlConnection connection; SqlCommand command; SqlDataAdapter adapter = new SqlDataAdapter(); DataSet ds = new DataSet(); int i = 0; string sql = null; connetionString = "Data Source=.;Initial Catalog=DatabaseName;User ID=UserName;Password=Password"; sql = "select au_id,au_lname from authors"; connection = new SqlConnection(connetionString); try { connection.Open(); command = new SqlCommand(sql, connection); adapter.SelectCommand = command; adapter.Fill(ds); adapter.Dispose(); command.Dispose(); connection.Close(); comboBox1.DataSource = ds.Tables[0]; comboBox1.ValueMember = "au_id"; comboBox1.DisplayMember = "au_lname"; } catch (Exception ex) { MessageBox.Show("Can not open connection ! "); } } private void button1_Click(object sender, EventArgs e) { MessageBox.Show(comboBox1.Text + " " + comboBox1.SelectedValue); } } }

Binding a ComboBox to an Enum values

Enums in C# provide a convenient way to define a group of related constants that can be represented as strings or integer values. Enums allow for easy selection of options by representing them as a list of string values, which can be bound to a ComboBox for user selection.

Data Binding an Enum with Descriptions

comboBox1.DataSource = Enum.GetValues(typeof(Colors)); comboBox1.SelectedItem = Colors.Green;

The follwoing C# program bind a combobox with Enum values.

using System; using System.Windows.Forms; using System.Collections.Generic; namespace WindowsFormsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } public enum Colors { Red = 10, Blue = 20, Green = 30, Yellow = 40, } private void button1_Click(object sender, EventArgs e) { MessageBox.Show(comboBox1.Text + " " + Convert.ToString((int)comboBox1.SelectedValue)); } private void Form1_Load(object sender, EventArgs e) { comboBox1.DataSource = Enum.GetValues(typeof(Colors)); comboBox1.SelectedItem = Colors.Green; } } }

Bind a ComboBox to a generic Dictionary

The Dictionary class in C# is a data structure that represents a collection of key-value pairs. Each key in the dictionary is unique, and it can have at most one associated value. However, a value can be associated with multiple keys. Dictionaries are useful for storing and accessing data based on unique keys.

Dictionary as a Combobox Datasource

comboBox1.DataSource = new BindingSource(colors, null); comboBox1.DisplayMember = "Value"; comboBox1.ValueMember = "Key";

The following C# program populating a Combobox from a Dictionary .

Full Source C#

using System; using System.Windows.Forms; using System.Collections.Generic; namespace WindowsFormsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { MessageBox.Show(Convert.ToString(comboBox1.Text + " " + comboBox1.SelectedValue)); } private void Form1_Load(object sender, EventArgs e) { var colors = new Dictionary < string, string > (); colors["10"] = "Red"; colors["20"] = "Blue"; colors["30"] = "Green"; colors["40"] = "Yellow"; comboBox1.DataSource = new BindingSource(colors, null); comboBox1.DisplayMember = "Value"; comboBox1.ValueMember = "Key"; } } }

Next > How to find tables in a Database in C#

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