Hi WiZZiX,

Based on my understanding, you programmatically change a bound control's
value then find the change did not reflect into the underlying datasouce.

For this issue, we have 2 options:
1. Explicitly changes the bound control's focus to force the databinding,
like this.
2. Invoke the EndCurrentEdit method on the bindingmanager for the CheckBox.
I suggest you use this way.

Sample code snippet below:
DataTable dt;
private void button1_Click(object sender, System.EventArgs e)
{
    dt=new DataTable();
    dt.Columns.Add(new DataColumn("prop1", typeof(bool)));
    dt.Columns.Add(new DataColumn("prop2", typeof(bool)));
    dt.Columns[0].DefaultValue=false;
    dt.Columns[0].DefaultValue=true;

    for(int i=0;i<3;i++)
    {
        DataRow dr=dt.NewRow();
        dr[0]=false;
        dr[1]=true;
        dt.Rows.Add(dr);
    }
    this.checkBox1.DataBindings.Add (new Binding("Checked", dt, "prop1"));
    this.checkBox2.DataBindings.Add (new Binding("Checked", dt, "prop2"));
}

private void checkBox1_CheckedChanged(object sender, System.EventArgs e)
{
    this.checkBox2.Checked=this.checkBox1.Checked;
    this.checkBox2.DataBindings[0].BindingManagerBase.EndCurrentEdit();
//    this.checkBox2.Focus();     //this is another option
//    this.checkBox1.Focus();
}

private void button2_Click(object sender, System.EventArgs e)
{
    MessageBox.Show(dt.Rows[0][1].ToString());
}
==============================================================
Please apply my suggestion above and let me know if it helps resolve your
problem.

Thank you for your patience and cooperation. If you have any questions or
concerns, please feel free to post it in the group. I am standing by to be
of assistance.

Best regards,
Jeffrey Tan
Microsoft Online Partner Support