In this article I will explain with an example, how to save CheckBoxList selected Items to SQL Server database and retain them on PostBacks in ASP.Net using C# and VB.Net.
 
 

Database

I have made use of the following table Hobbies with the schema as follows.
Save CheckBoxList selected items and retain them on PostBacks in ASP.Net
 
I have already inserted few records in the table
Save CheckBoxList selected items and retain them on PostBacks in ASP.Net
 
Note: You can download the database table SQL by clicking the download link below.
          Download SQL file
 
 

HTML Markup

The following HTML Markup consists of:
CheckBoxList – For displaying data.
Button – For updating records in the SQL Server database.
The Button has been assigned with an OnClick event handler.
Hobbies:
<asp:CheckBoxList ID="chkHobbies" runat="server"></asp:CheckBoxList>
<br />
<asp:Button ID="btnUpdate" runat="server" Text="Update" OnClick="UpdateHobbies" />
 
 

Binding the CheckBoxList from Database

Inside the Page Load event handler, the PopulateHobbies method is called.

PopulateHobbies

Inside the PopulateHobbies method, the records are fetched from the SQL Server database table using ExecuteReader function.
Note: For more details on ExecuteReader function, please refer Using SQLCommand ExecuteReader Example in ASP.Net with C# and VB.Net.
 
The checked and unchecked state of CheckBoxList will be decided based on IsSelected column value which is set from the SQL Server database.
If the value of IsSelected column is TRUE, then the CheckBox will be checked and if it is FALSE, then the CheckBox will be set as unchecked.
C#
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.PopulateHobbies();
    }
}
 
private void PopulateHobbies()
{
    string query = "SELECT HobbyId, Hobby, IsSelected FROM Hobbies";
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand(query, con))
        {
            con.Open();
            using (SqlDataReader sdr = cmd.ExecuteReader())
            {
                while (sdr.Read())
                {
                    ListItem item = new ListItem();
                    item.Text = sdr["Hobby"].ToString();
                    item.Value = sdr["HobbyId"].ToString();
                    item.Selected = Convert.ToBoolean(sdr["IsSelected"]);
                    chkHobbies.Items.Add(item);
               }
            }
            con.Close();
        }
    }
}
 
VB.Net
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Me.PopulateHobbies()
    End If
End Sub
 
Private Sub PopulateHobbies()
    Dim query As String = "SELECT HobbyId, Hobby, IsSelected FROM Hobbies"
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As SqlConnection = New SqlConnection(constr)
        Using cmd As SqlCommand = NewSqlCommand(query, con)
            con.Open()
            Using sdr As SqlDataReader = cmd.ExecuteReader()
                While sdr.Read()
                    Dim item As ListItem = New ListItem()
                    item.Text = sdr("Hobby").ToString()
                    item.Value = sdr("HobbyId").ToString()
                    item.Selected = Convert.ToBoolean(sdr("IsSelected"))
                    chkHobbies.Items.Add(item)
                End While
            End Using
            con.Close()
        End Using
    End Using
End Sub
 
 

Update selected value of CheckBoxList to SQL Server

When the Update button is clicked, a FOR EACH loop will be executed over the CheckBoxList items and the records are updated into the SQL Server database table based on the state of CheckBoxes in CheckBoxList using ExecuteNonQuery method.
Note: For more details on how to use ExecuteNonQuery function, please refer Understanding SqlCommand ExecuteNonQuery in C# and VB.Net.
 
C#
protected void UpdateHobbies(object sender, EventArgs e)
{
    string query = "UPDATE Hobbies SET IsSelected = @IsSelected WHERE HobbyId = @HobbyId";
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand(query, con))
        {
            foreach (ListItem item in chkHobbies.Items)
            {
                cmd.Parameters.Clear();
                cmd.Parameters.AddWithValue("@IsSelected", item.Selected);
                cmd.Parameters.AddWithValue("@HobbyId", item.Value);
                con.Open();
                cmd.ExecuteNonQuery();
                con.Close();
            }
        }
    }
}
 
VB.Net
Protected Sub UpdateHobbies(ByVal sender As Object, ByVal e As EventArgs )
    Dim query As String = "UPDATE Hobbies SET IsSelected = @IsSelected WHERE HobbyId = @HobbyId"
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As SqlConnection = New SqlConnection(constr)
        Using cmd As SqlCommand = New SqlCommand(query, con)
            For Each item As ListItem In chkHobbies.Items
                cmd.Parameters.Clear()
                cmd.Parameters.AddWithValue("@IsSelected", item.Selected)
                cmd.Parameters.AddWithValue("@HobbyId", item.Value)
                con.Open()
                cmd.ExecuteNonQuery()
                con.Close()
            Next
        End Using
    End Using
End Sub
 
 

Screenshots

The Form

Save CheckBoxList selected items and retain them on PostBacks in ASP.Net
 

Records after Updating

Save CheckBoxList selected items and retain them on PostBacks in ASP.Net
 
 

Demo

View Demo
 
 

Downloads

Download Code