The problem:
In a DataGridView control, after adding a new row, and clicking away, the new row just disappears without any visible error.

The solution:
This is most likely caused by an error being raised due to a data input error. Im my case it was because of a non visible column not allowing nulls.
To find out if this is the cause of yoyr issue, put a break point in the DataError event handler. Even though the error might have beeen written to the row's ErrorText, it is never displayed because the row disappears.

As promised I've published the code and instructions to my previous post...
Go and have a look on CodeProject:

Workaround: svn:externals with a space in the directory name:
TSVN Post-Update hook utility for using svn:externals with a space in the directory name
http://www.codeproject.com/KB/files/Percent20toSpace.aspx

Please let me know what you think.

While setting up my development environment for various BlogEngine.NET sites, I ran into the problem that when setting svn:externals: One cannot have spaces in the directory name or the external url with TortoiseSVN.
For example: User controls svn://host/User controls
According to a message in the TSVN mailing list, the trick is to replace the space with "%20", like this: User%20controls svn://host/User%20controls Now being able to add the external, there is a new problem:
When I put the "%20" in the name, I get a directory with the characters "%20" in the name. I could have just used an underscore, but the there are references to the "User controls" directory in the project and for future compatibility I didn't want to deviate from the original structure.

To overcome this I've created a tiny console application to rename the directory when the TSVN Post-Update Hook is fired. I will post the source in the next edition of this saga.

A friend asked me for an example of a lamda expression, and after going through my code and searching the net, I discovered this little gold nugget:

A lambda expression is a way of creating a function without giving it a name.

Suppose you defined: bool blah(n) { return n%2 == 1; } That's a function named blah. (n => n%2 == 1) int[] numbers = {5,4,1,3,9,8,6,7,2,0 }; int oddNumbers = numbers.Count(n => n % 2 == 1); "numbers" is the sequence. It's an array, implementing IEnumerable<int>.
If you just call numbers.Count() you'll get 10. The version with the lambda expression is saying "only count elements which match this predicate".
It's sort of similar to calling: numbers.Where(n => n % 2 == 1).Count();
Reference:
http://www.eggheadcafe.com/software/aspnet/31850595/confused-about-the-lamda.aspx

I was using the Current property of a BindingSource object in VB.Net for sometime now using inplicit conversions to access fields:

MyBindingSource.Current(0) = someValue While in C# we need to explicitly cast the Current property to some type and use that. I tried using typeof(...) and got this peculiar result...
typeof(MyBindingSource.Current) 'Myproject.Form1.MyBindingSource' is a 'field' but is used like a 'type'

Then I tried .ToSting(), and this had a more promising result...
MyBindingSource.Current.ToString() "System.Data.DataRowView"

So, if you want to access a field in a BindingSource:
DataRowView drv = MyBindingSource.Current as DataRowView; drv[0] = someValue; //or assignment (if the field's type is an int) int someValue = Convert.ToInt32(drv[0]);
Hope i save someone five minutes.

On to the next hurdle (sigh).

The problem:
In a DataGridView, when deleting the last remaining data row, the UserDeletedRow event does not fire.

The solution:
To work around this we need to add some logic to the UserDeletingRow event handler to count the number of rows and call the event handler when necessary... private void DataGridView1_UserDeletingRow(object sender, DataGridViewRowCancelEventArgs e) {    if (DataGridView1.RowCount == (DataGridView1.AllowUserToAddRows ? 2 : 1))       DataGridView1_UserDeletedRow(DataGridView1, new DataGridViewRowEventArgs(e.Row)); } private void DataGridView1_UserDeletedRow(object sender, DataGridViewRowEventArgs e) {    // do something here... }

Hi, this is number two of my Binding error series.

I've got a BindingSource setup with the Sort property set to a valid column name and all works well, (dejavu) but the problem is when the form closes, and starts Disposing controls, I get this message:
"Sort string contains a property that is not in the IBindingList."

The solution is almost the same as in Part 1, but this time we want to clear the Sort property of all BindingSources on the form...
/// <summary> /// Clean up any resources being used. /// </summary> /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param> protected override void Dispose(bool disposing) {    try {       if (disposing && (null != components)) {          foreach (System.ComponentModel.IComponent comp in components.Components) {             if (comp is System.Windows.Forms.BindingSource)                (comp as System.Windows.Forms.BindingSource).Sort = null;          }          components.Dispose();       }    } finally {       base.Dispose(disposing);    } }

Notice the bit where we loop through the components to be disposed of. Now Isn't this fun!

I've recently had to work on a project using DataBinding. All seemed to go well until I ran into some strange issues.

This is the first of a few posts describing these issues and how to work around them.

I've got some bound ComboBox columns in a bound DataGridView and all works well, but the problem is when the form closes, and starts Disposing controls, I get this message:

"Message: ArgumentException: Cannot bind to the property or column State on the DataSource. Parameter name: dataMember"

It seems to affect the ComboBoxes bound to the NameValueLists where the Text property is databound. The solution is to clear all DataBinding before Dispose().

Step 1: Create a method to clear DataBinding recursively... using System; using System.Collections.Generic; using System.Text; using System.Windows.Forms; using System.ComponentModel; using System.Reflection; namespace DataBinding {    internal sealed class Utilities {       /// <summary>       /// Clears all databindings from the control and all child controls.       /// </summary>       /// <param name="ctl">The control from which to clear the databindings.</param>       public static void ClearBindings(Control ctl) {          Binding[] bindings = new Binding[ctl.DataBindings.Count];          ctl.DataBindings.CopyTo(bindings, 0);          ctl.DataBindings.Clear();                    foreach (Binding bnd in bindings)              if (null != bnd) TypeDescriptor.Refresh(bnd.DataSource);                    PropertyInfo dataSourceProperty = ctl.GetType().GetProperty("DataSource");          object[] obj = new object[]{};          if (null != dataSourceProperty)             dataSourceProperty.SetValue(ctl, null, obj);                    foreach (Control child in ctl.Controls)             ClearBindings(child);       }    } } Step 2: Call the ClearBindings method when the Form has been closed... private void Form1_FormClosed(object sender, FormClosedEventArgs e) {    // Release bindings    Utilities.ClearBindings(this); }

That should do the trick.

C# port of svnperms.py pre-commit hook script.

I've just posted my first article to The Code project.
Check it out at SvnPerms dot Net.