"There is no source code available for the current location"

Hi,

I was hoping someone could help me with the following problem.

I have a user control in C# which is displaying the message "There is no source code available for the current location" (there is nothing else in the message) when I step through the validate function attached to a textbox control. I've isolated the problem and attached the source code below for this. I've had a look on the internet for postings regarding this issue and am doing everything that is recommended.

It seems that there are four things required for this message to come up:
1. The controls need to be bound to an underlying data source,
2. The error provider (which is a multithreaded control) needs to have been added to the control (even if the errorprovider is removed, something seems to have changed to cause this to come up)
3. This seems to happen after the user code for the validate method has finished executing, but before control is returned to the form (in debug mode)
4. I need to have added a new empty row to the underlying data source (I'm doing this to enture that the combo boxes in the fullblown app where I first notioced this have a blank default value - if anyone can suggest another way of going about this in the front end without adding a blank row to the table in the database, then that would be great too).

It seems that this is arising when there is multithreading - other postings indicate this happens during recursion or multithreading or when using certain timer controls.

I'm not getting this message when the application runs - just in debug mode. The app's general functionality does not seem to be affected - everything is behaving as it should be. However, what makes me worried is that some of the internet postings indicate that this is happening because an error is being thrown somewhere else in my code and is being handled strangely. Am I doing something wrong / weird  

Any help would be appreciated. Please let me know if I've left anything out or have been unclear.

Thank you
Nicole

**********************************
// CODE FOLLOWS
*********************************

/* user control contains a textbox called txtInput and button to force validation when tabbing / clicking off the textbox control. It also contains an error provider called errorProvider1. This user control can be inserted into Form1 in a dummy app to reproduce the issue */

using System;

using System.Collections;

using System.ComponentModel;

using System.Drawing;

using System.Data;

using System.Windows.Forms;

namespace WindowsApplication1

/// <summary>

/// Contains the bug regarding "There is no source code available for the current location".

/// </summary>

public class UserControl1 : System.Windows.Forms.UserControl

{
private System.Windows.Forms.ErrorProvider errorProvider1;
/// <summary>
/// Required designer variable.
/// </summary>

private System.ComponentModel.Container components = null;
private DataSet MyDataSet;
private DataTable MyTable;
private CurrencyManager MyCurrencyManager;
private System.Windows.Forms.Button btnSave;
private System.Windows.Forms.TextBox txtInput;

// Default constructor.
public UserControl1()
{
// This call is required by the Windows.Forms Form Designer.
InitializeComponent();
InitSelf();
CreateNewRow();
}

private void CreateNewRow()
{
// add a new row to the table - do this because
// we don't want drop-downs to display the first
// value in the drop-down data list
MyTable.Rows.Add( MyTable.NewRow() );
}

private void InitSelf()
{
MyDataSet = new DataSet();
InitTables();
InitControls();
}

private void InitControls()
{
txtInput.DataBindings.Add( "Text", MyDataSet, "Table.Input" );
MyCurrencyManager = (CurrencyManager) this.BindingContext[MyDataSet, "Table" ];
}

private void InitTables()
{
// Input table
DataColumn c;
MyTable = new DataTable( "Table" );
// columns
c = new DataColumn( "InputID", System.Type.GetType( "System.Int32" ) );
MyTable.Columns.Add(c);
c = new DataColumn( "Input", System.Type.GetType( "System.String" ) );
MyTable.Columns.Add(c);

// primary key
DataColumn pkColumn = MyTable.Columns["InputID"];
pkColumn.AutoIncrement = true;
pkColumn.AutoIncrementSeed = -1;
pkColumn.AutoIncrementStep = -1;
pkColumn.ReadOnly = true;
MyTable.PrimaryKey = new DataColumn[] {pkColumn};
MyDataSet.Tables.Add( MyTable );
}

/// <summary>
/// Clean up any resources being used.
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if(components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
}

#region Component Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.errorProvider1 = new System.Windows.Forms.ErrorProvider();
this.btnSave = new System.Windows.Forms.Button();
this.txtInput = new System.Windows.Forms.TextBox();
this.SuspendLayout();
//
// errorProvider1
//
this.errorProvider1.ContainerControl = this;
//
// btnSave
//
this.btnSave.Location = new System.Drawing.Point(320, 160);
this.btnSave.Name = "btnSave";
this.btnSave.TabIndex = 0;
this.btnSave.Text = "Save";
//
// txtInput
//
this.txtInput.Location = new System.Drawing.Point(88, 152);
this.txtInput.Name = "txtInput";
this.txtInput.TabIndex = 1;
this.txtInput.Text = "textBox1";
this.txtInput.Validating += new System.ComponentModel.CancelEventHandler(this.txtInput_Validating);
//
// UserControl1
//
this.Controls.Add(this.txtInput);
this.Controls.Add(this.btnSave);
this.Name = "UserControl1";
this.Size = new System.Drawing.Size(528, 464);
this.ResumeLayout(false);
}
#endregion

private void txtInput_Validating(object sender, System.ComponentModel.CancelEventArgs e)
{// put a breakpoint here
// exiting this function in debug mode raises the error message:
//"There is no source code available for the current location".
}