Populate tree from 3 different data sources and show its content

The task is to build a WinForm app which populates a tree from 3 different data sources and shows its content.

• 1 ComboBox at top - to choose datasource. (File System, XMLFile, SQLDB)

• 1 Button next to ComboBox - to select datasource path. (Or Connection String)

• 1 TreeView Control at left - to show tree.

• 1 RichTextBox to show content. (in case of file system showing txt files content).

MainForm.cs:

```
public partial class MainForm : Form
{
private TreeProvider treeProvider;
private Action pathSelectFunction;

public MainForm()
{
InitializeComponent();
InitializeDataSourceComboBox();
}

private void InitializeDataSourceComboBox()
{
DataSourceComboBox.DataSource = ConfigurationManager.DataSourceTypes.dataSourceTypes;
DataSourceComboBox.ValueMember = "Type";
DataSourceComboBox.DisplayMember = "Name";
}

private void DataSourceComboBox_SelectedIndexChanged(object sender, EventArgs e)
{
DataSourceType selItem = (DataSourceType)DataSourceComboBox.SelectedItem;
switch (selItem.Type)
{
case "XMLFile":
SelectDataSourcePathButton.Text = "Select XML File";
pathSelectFunction = SelectXMLFilePath;
break;
case "FileSystem":
SelectDataSourcePathButton.Text = "Select Root Folder";
pathSelectFunction = SelectRootFolderPath;
break;
case "SQLDB":
SelectDataSourcePathButton.Text = "Specify SQL connection string";
break;
default:
return;
}
}

private void SelectDataSourcePathButton_Click(object sender, EventArgs e)
{
pathSelectFunction();
}

private void SelectXMLFil

• The usual whitespace/egyptian brackets mumbo-jumbo.

NodeBase nodeBase = new NodeBase() ;
    try{
        nodeBase.Identity = directory.Name;
        nodeBase.ParentIdentity = directory.Parent.FullName;

Should be:

NodeBase nodeBase = new NodeBase();

    try
    {
        nodeBase.Identity = directory.Name;
        nodeBase.ParentIdentity = directory.Parent.FullName;

Etc.

-
Did you mean for the internal classes?

class FileSystemTreeSource : ITreeSource
class SQLTreeSource : ITreeSource
public class XMLTreeSource : ITreeSource

Notice that XMLTreeSource is the only one that is public.

If you did want them to be internal, I suggest adding the internal keyword in front of them to be explicit about it.

• Naming nitpicks:

• XMLTreeSource should be XmlTreeSource;

• GetXMLDOM should be GetXmlDom;

• SQLTreeSource should be SqlTreeSource;

• etc.

This is to fall in line with the best-practices of PascalCasing.

-
Your SQL should be parameterized queries instead. As it stands you are very open to SQL injection. (What would happen if I specified a tableName of Table; DROP TABLE Customers;? Not good things, I suggest.)

-
Usually I tend to favour immutability over mutability.

public string Identity { get; set; }
public string ParentIdentity { get; set; }
public string Content { get; set; }
public int ChildCount { get; set; }

Those set actions should be private.

Unless you absolutely have a need for mutability, you should try to favour immutability. It leaves you less vulnerable to problems with data validation, et al.

StackExchange Code Review Q#98693, answer score: 4