Dear Cypher,

Thanks for the information.

The Checked property of the RadioButton control is defined as bool, so only
boolean values can be assigned to this property. When there are null values
in the IsActive field, they're treated as DbNull objects when performing
the data binding. The cast from DbNull type to bool type is invalid,
resulting in this error message.

To avoid this error message, you can try two approach:

1. Handle the Format event of the Binding object to assign a boolen value
for the Checked property when the ConvertEventArgs.Value is DbNull.Value.

       private void Form1_Load(object sender, EventArgs e)
       {
           string connstr =
Properties.Settings.Default.Database1ConnectionString;
           
           SqlConnection conn = new SqlConnection(connstr);
           string sql = "SELECT * From Table1";
           SqlDataAdapter da = new SqlDataAdapter(sql, conn);
           DataSet ds = new DataSet();
           da.Fill(ds, "test");

           Binding binding = new Binding("checked", ds.Tables[0],
"IsActive");
           binding.Format += new ConvertEventHandler(binding_Format);
           this.radioButton1.DataBindings.Add(binding);
       }

       void binding_Format(object sender, ConvertEventArgs e)
       {
           if (e.Value == DBNull.Value)
           {
               e.Value = false;//or e.Value = true;
           }
       }

2. Change the table definition to not allow null values on the IsActive
field.

Please try my suggestions and let me know the result. If anything is
unclear, don't hesitate to let me know.

Sincerely,
Zhi-Xin Ye
Microsoft Managed Newsgroup Support Team

Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
msdnmg@microsoft.com.

This posting is provided "AS IS" with no warranties, and confers no rights.