Code for Dynamically set the database(Connection String) for the project

Code for Dynamically set the database for the project
a)In button click event you can set the databse using database properties.
b)In another button click you can access from configuration settings for SQLdataadapter

sample code in c#.net shown below:

private void button1_Click(object sender, EventArgs e)
{
Microsoft.Data.ConnectionUI.DataConnectionDialog dcd=new Microsoft.Data.ConnectionUI.DataConnectionDialog();
Microsoft.Data.ConnectionUI.DataSource.AddStandardDataSources(dcd);
if (Microsoft.Data.ConnectionUI.DataConnectionDialog.Show(dcd) == DialogResult.OK)
{
textBox1.Text = dcd.ConnectionString;
ConnectionStringsSection Section=new ConnectionStringsSection();
ConnectionStringSettings Setting;
Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);

Section = (ConnectionStringsSection)(config.GetSection("connectionStrings"));
if (Section.ConnectionStrings["ConString"]==null)
{

Section.ConnectionStrings.Add(new ConnectionStringSettings("ConString", dcd.ConnectionString));

}
Setting = Section.ConnectionStrings["ConString"];
Setting.ConnectionString = dcd.ConnectionString;
ConfigurationManager.RefreshSection("connectionStrings");

config.Save(ConfigurationSaveMode.Modified, true);
ConfigurationManager.RefreshSection("connectionStrings");


}
else
{
textBox1.Text = "";
}
}

private void button2_Click(object sender, EventArgs e)
{

System.Data.SqlClient.SqlDataAdapter da = new System.Data.SqlClient.SqlDataAdapter("select *from Testing",System.Configuration.ConfigurationManager.ConnectionStrings["ConString"].ConnectionString );
da.Fill(ds);
dataGridView1.DataSource = ds.Tables[0];

}

Code for How to Add Combobox Columns to datagridview in VB.Net

'Get a reference to the default DataView of the table
Dim dv As DataView = dt.DefaultView


'Create 2 combo box columns: Set DisplayMember, ValueMember and DataSource
Dim colQty1 As New DataGridViewComboBoxColumn

()
colQty1.DisplayMember = "Quantity1"
colQty1.ValueMember = "Quantity1"
colQty1.HeaderText = "Quantity 1"
colQty1.DataSource = dv

Dim colQty2 As New DataGridViewComboBoxColumn()
colQty2.DisplayMember = "Quantity2"
colQty2.ValueMember = "Quantity2"
colQty2.HeaderText = "Quantity 2"
colQty2.DataSource = dv

'Add both columns to it
dgv.Columns.AddRange(New DataGridViewColumn() {colQty1, colQty2})