Exploring DataGridViewComboBoxColumn databinding (part2)

A while ago i wrote about Exploring DataGridViewComboBoxColumn databinding using Business Objects. Some people asked me to give an example using DataSets…

I’ll start with creating a DataSet, add two DataTables, and create a relation on PersonType.Id (int32). In the designer this looks like:

Next i create a DataSetDac that will return an instance of a Filled PersonDataSet (In real life you would probably use a TableAdapter and get the data from a database) The code is as simple as:

public static PersonsDataSet Find()
{
 PersonsDataSet personsDataSet = new PersonsDataSet();

 personsDataSet.PersonType.Rows.Add(new object[] { 0, "A geeky person" });
 personsDataSet.PersonType.Rows.Add(new object[] { 1, "A coward" });
 personsDataSet.PersonType.Rows.Add(new object[] { 2, "Feeling hot hot hot" });
 personsDataSet.PersonType.Rows.Add(new object[] { -1, "(None)" });

 personsDataSet.Person.Rows.Add(new object[] { "Timvw", 0 });
 personsDataSet.Person.Rows.Add(new object[] { "John Doe", 1 });
 personsDataSet.Person.Rows.Add(new object[] { "An Onymous", 1 });
 personsDataSet.Person.Rows.Add(new object[] { "Jenna Jameson", 2 });
 personsDataSet.Person.Rows.Add(new object[] { "Null Able", -1 });

 return personsDataSet;
}

And now comes the important stuff: Bind the data to the DataGridView and DataGridViewComboBoxColumn:

public Form1()
{
 InitializeComponent();

 PersonsDataSet personsDataSet = DataSetDac.Find();

 this.dataGridView1.AutoGenerateColumns = false;
 this.ColumnName.DataPropertyName = "Name";
 this.ColumnPersonTypeCode.DataPropertyName = "PersonTypeId";

 this.ColumnPersonTypeCode.DisplayMember = "Label";
 this.ColumnPersonTypeCode.ValueMember = "Id";
 this.ColumnPersonTypeCode.DataSource = personsDataSet.PersonType;

 BindingSource bindingSource = new BindingSource();
 bindingSource.DataSource = personsDataSet.Person;
 this.dataGridView1.DataSource = bindingSource;
}

Geeks are doomed to stay Geeks forever. When you try change a Person that is a Geek, the values in ComboBox should be limited to Geek and (None). The following code takes care of that:

void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
 if (this.dataGridView1.CurrentCell.ColumnIndex == this.ColumnPersonTypeCode.Index)
 {
  BindingSource bindingSource = this.dataGridView1.DataSource as BindingSource;
  PersonsDataSet.PersonRow person = (bindingSource.Current as DataRowView).Row as PersonsDataSet.PersonRow;

  // this method returns the allowed persontypes for the given person
  PersonsDataSet.PersonTypeDataTable personTypeDataTable = DataSetDac.FindPersonTypes(person);

  DataGridViewComboBoxEditingControl comboBox = e.Control as DataGridViewComboBoxEditingControl;
  comboBox.DataSource = personTypeDataTable;

  comboBox.SelectionChangeCommitted -= this.comboBox_SelectionChangeCommitted;
  comboBox.SelectionChangeCommitted += this.comboBox_SelectionChangeCommitted;
 }
}

public static PersonsDataSet.PersonTypeDataTable FindPersonTypes(PersonsDataSet.PersonRow person)
{
 // by default, all persons simply have one of the available persontypecodes
 PersonsDataSet personsDataSet = Find();

 if (person.PersonTypeId.Equals(0))
 {
  // geeks are doomed to stay geeks
  personsDataSet.PersonType.Rows.RemoveAt(2);
  personsDataSet.PersonType.Rows.RemoveAt(1);
 }

 return personsDataSet.PersonType;
}

void comboBox_SelectionChangeCommitted(object sender, EventArgs e)
{
 this.dataGridView1.EndEdit();
}

As always, feel free to download DataGridViewComboBoxBinding2.zip.