C# -- datagridview 에서 virtual mode 사용하기

C# -- datagridview 에서 virtual mode 사용하기

참고 : https://docs.microsoft.com/ko-kr/dotnet/framework/winforms/controls/implementing-virtual-mode-wf-datagridview-control

           ---> row-level commit scope

        https://docs.microsoft.com/ko-kr/dotnet/api/system.windows.forms.datagridview.virtualmode?view=netframework-4.8

          ---> cell-level commit scope

        https://docs.microsoft.com/en-us/dotnet/framework/winforms/controls/virtual-mode-in-the-windows-forms-datagridview-control

** VirtualMode 전용 event

   -- 읽기 전용인 경우는, CellValueNeeded event 만 사용하면 됨.

<< 실행 화면 1 -- row-level commit scope >>

<< 실행 화면 2 -- cell-level commit scope >>

<< 소스 1 -- row-level commit scope >>

	using System;
	using System.Collections;
	using System.Collections.Generic;
	using System.ComponentModel;
	using System.Data;
	using System.Drawing;
	using System.Linq;
	using System.Text;
	using System.Threading.Tasks;
	using System.Windows.Forms;
	namespace DataGridView_VirtalMode_test1
	{
	public partial class Form1 : Form
	{
	private DataGridView dataGridView1 = new DataGridView();
	// Declare an ArrayList to serve as the data store.
	private ArrayList customers = new ArrayList();
	// Declare a Customer object to store data for a row being edited.
	private Customer customerInEdit;
	// Declare a variable to store the index of a row being edited.
	// A value of -1 indicates that there is no row currently in edit.
	private int rowInEdit = -1;
	// Declare a variable to indicate the commit scope.
	// Set this value to false to use cell-level commit scope.
	private bool rowScopeCommit = true;
	public Form1()
	{
	InitializeComponent();
	// Initialize the form.
	this.dataGridView1.Dock = DockStyle.Fill;
	this.Controls.Add(this.dataGridView1);
	//this.Load += new EventHandler(Form1_Load);
	this.Text = "DataGridView virtual-mode demo (row-level commit scope)";
	}
	private void Form1_Load(object sender, EventArgs e)
	{
	// Enable virtual mode.
	this.dataGridView1.VirtualMode = true;
	// Connect the virtual-mode events to event handlers.
	this.dataGridView1.CellValueNeeded += new
	DataGridViewCellValueEventHandler(dataGridView1_CellValueNeeded);
	this.dataGridView1.CellValuePushed += new
	DataGridViewCellValueEventHandler(dataGridView1_CellValuePushed);
	this.dataGridView1.NewRowNeeded += new
	DataGridViewRowEventHandler(dataGridView1_NewRowNeeded);
	this.dataGridView1.RowValidated += new
	DataGridViewCellEventHandler(dataGridView1_RowValidated);
	this.dataGridView1.RowDirtyStateNeeded += new
	QuestionEventHandler(dataGridView1_RowDirtyStateNeeded);
	this.dataGridView1.CancelRowEdit += new
	QuestionEventHandler(dataGridView1_CancelRowEdit);
	this.dataGridView1.UserDeletingRow += new
	DataGridViewRowCancelEventHandler(dataGridView1_UserDeletingRow);
	// Add columns to the DataGridView.
	DataGridViewTextBoxColumn companyNameColumn = new
	DataGridViewTextBoxColumn();
	companyNameColumn.HeaderText = "Company Name";
	companyNameColumn.Name = "Company Name";
	DataGridViewTextBoxColumn contactNameColumn = new
	DataGridViewTextBoxColumn();
	contactNameColumn.HeaderText = "Contact Name";
	contactNameColumn.Name = "Contact Name";
	this.dataGridView1.Columns.Add(companyNameColumn);
	this.dataGridView1.Columns.Add(contactNameColumn);
	this.dataGridView1.AutoSizeColumnsMode =
	DataGridViewAutoSizeColumnsMode.AllCells;
	// Add some sample entries to the data store.
	this.customers.Add(new Customer(
	"Bon app'", "Laurence Lebihan"));
	this.customers.Add(new Customer(
	"Bottom-Dollar Markets", "Elizabeth Lincoln"));
	this.customers.Add(new Customer(
	"B's Beverages", "Victoria Ashworth"));
	// Set the row count, including the row for new records.
	this.dataGridView1.RowCount = 4;
	}
	private void dataGridView1_UserDeletingRow(object sender, DataGridViewRowCancelEventArgs e)
	{
	if (e.Row.Index < this.customers.Count)
	{
	// If the user has deleted an existing row, remove the
	// corresponding Customer object from the data store.
	this.customers.RemoveAt(e.Row.Index);
	}
	if (e.Row.Index == this.rowInEdit)
	{
	// If the user has deleted a newly created row, release
	// the corresponding Customer object.
	this.rowInEdit = -1;
	this.customerInEdit = null;
	}
	}
	private void dataGridView1_CancelRowEdit(object sender, QuestionEventArgs e)
	{
	if (this.rowInEdit == this.dataGridView1.Rows.Count - 2 && this.rowInEdit == this.customers.Count)
	{
	// If the user has canceled the edit of a newly created row,
	// replace the corresponding Customer object with a new, empty one.
	this.customerInEdit = new Customer();
	}
	else
	{
	// If the user has canceled the edit of an existing row,
	// release the corresponding Customer object.
	this.customerInEdit = null;
	this.rowInEdit = -1;
	}
	}
	private void dataGridView1_RowDirtyStateNeeded(object sender, QuestionEventArgs e)
	{
	if (!rowScopeCommit)
	{
	// In cell-level commit scope, indicate whether the value
	// of the current cell has been modified.
	e.Response = this.dataGridView1.IsCurrentCellDirty;
	}
	}
	private void dataGridView1_RowValidated(object sender, DataGridViewCellEventArgs e)
	{
	// Save row changes if any were made and release the edited
	// Customer object if there is one.
	if (e.RowIndex >= this.customers.Count &&
	e.RowIndex != this.dataGridView1.Rows.Count - 1)
	{
	// Add the new Customer object to the data store.
	this.customers.Add(this.customerInEdit);
	this.customerInEdit = null;
	this.rowInEdit = -1;
	}
	else if (this.customerInEdit != null &&
	e.RowIndex < this.customers.Count)
	{
	// Save the modified Customer object in the data store.
	this.customers[e.RowIndex] = this.customerInEdit;
	this.customerInEdit = null;
	this.rowInEdit = -1;
	}
	else if (this.dataGridView1.ContainsFocus)
	{
	this.customerInEdit = null;
	this.rowInEdit = -1;
	}
	}
	private void dataGridView1_NewRowNeeded(object sender, DataGridViewRowEventArgs e)
	{
	// Create a new Customer object when the user edits
	// the row for new records.
	this.customerInEdit = new Customer();
	this.rowInEdit = this.dataGridView1.Rows.Count - 1;
	}
	// 변경된 셀 값에 내부 데이터 원본의 스토리지가 필요할 때 발생
	private void dataGridView1_CellValuePushed(object sender, DataGridViewCellValueEventArgs e)
	{
	Customer customerTmp = null;
	// Store a reference to the Customer object for the row being edited.
	if (e.RowIndex < this.customers.Count)
	{
	// If the user is editing a new row, create a new Customer object.
	this.customerInEdit = new Customer(
	((Customer)this.customers[e.RowIndex]).CompanyName,
	((Customer)this.customers[e.RowIndex]).ContactName);
	customerTmp = this.customerInEdit;
	this.rowInEdit = e.RowIndex;
	}
	else
	{
	customerTmp = this.customerInEdit;
	}
	// Set the appropriate Customer property to the cell value entered.
	String newValue = e.Value as String;
	switch (this.dataGridView1.Columns[e.ColumnIndex].Name)
	{
	case "Company Name":
	customerTmp.CompanyName = newValue;
	break;
	case "Contact Name":
	customerTmp.ContactName = newValue;
	break;
	}
	}
	// DataGridView에서 셀을 서식 지정하고 표시하기 위해 셀에 대한 값이 필요할 때 발생합니다.
	private void dataGridView1_CellValueNeeded(object sender, DataGridViewCellValueEventArgs e)
	{
	// If this is the row for new records, no values are needed.
	if (e.RowIndex == this.dataGridView1.RowCount - 1) return;
	Customer customerTmp = null;
	// Store a reference to the Customer object for the row being painted.
	if (e.RowIndex == rowInEdit)
	{
	customerTmp = this.customerInEdit;
	}
	else
	{
	customerTmp = (Customer)this.customers[e.RowIndex];
	}
	// Set the cell value to paint using the Customer object retrieved.
	switch (this.dataGridView1.Columns[e.ColumnIndex].Name)
	{
	case "Company Name":
	e.Value = customerTmp.CompanyName;
	break;
	case "Contact Name":
	e.Value = customerTmp.ContactName;
	break;
	}
	}
	}
	public class Customer
	{
	private String companyNameValue;
	private String contactNameValue;
	public Customer()
	{
	// Leave fields empty.
	}
	public Customer(String companyName, String contactName)
	{
	companyNameValue = companyName;
	contactNameValue = contactName;
	}
	public String CompanyName
	{
	get
	{
	return companyNameValue;
	}
	set
	{
	companyNameValue = value;
	}
	}
	public String ContactName
	{
	get
	{
	return contactNameValue;
	}
	set
	{
	contactNameValue = value;
	}
	}
	}
	}

view raw DataGridView_VirtualMode_row_level_commit_scope.cs hosted with ❤ by GitHub

<< 소스 2 -- cell-level commit scope >>

	using System;
	using System.Collections.Generic;
	using System.ComponentModel;
	using System.Data;
	using System.Drawing;
	using System.Linq;
	using System.Text;
	using System.Threading.Tasks;
	using System.Windows.Forms;
	namespace DataGridView_VirtualMode_test3
	{
	public partial class Form1 : Form
	{
	DataGridView dataGridView1 = new DataGridView();
	public Form1()
	{
	InitializeComponent();
	Text = "DataGridView virtual-mode demo (cell-level commit scope)";
	dataGridView1.NewRowNeeded +=
	new DataGridViewRowEventHandler(dataGridView1_NewRowNeeded);
	dataGridView1.RowsAdded +=
	new DataGridViewRowsAddedEventHandler(dataGridView1_RowsAdded);
	dataGridView1.CellValidating +=
	new DataGridViewCellValidatingEventHandler(dataGridView1_CellValidating);
	dataGridView1.CellValueNeeded +=
	new DataGridViewCellValueEventHandler(dataGridView1_CellValueNeeded);
	dataGridView1.CellValuePushed +=
	new DataGridViewCellValueEventHandler(dataGridView1_CellValuePushed);
	Controls.Add(dataGridView1);
	dataGridView1.VirtualMode = true;
	dataGridView1.AllowUserToDeleteRows = false;
	dataGridView1.Columns.Add("Numbers", "Positive Numbers");
	dataGridView1.Rows.AddCopies(0, initialSize);
	}
	bool newRowNeeded;
	private void dataGridView1_NewRowNeeded(object sender, DataGridViewRowEventArgs e)
	{
	newRowNeeded = true;
	}
	const int initialSize = 5000000;
	int numberOfRows = initialSize;
	private void dataGridView1_RowsAdded(object sender, DataGridViewRowsAddedEventArgs e)
	{
	if (newRowNeeded)
	{
	newRowNeeded = false;
	numberOfRows = numberOfRows + 1;
	}
	}
	#region "data store maintance"
	const int initialValue = -1;
	private void dataGridView1_CellValueNeeded(object sender, DataGridViewCellValueEventArgs e)
	{
	if (store.ContainsKey(e.RowIndex))
	{
	// Use the store if the e value has been modified
	// and stored.
	e.Value = store[e.RowIndex];
	}
	else if (newRowNeeded && e.RowIndex == numberOfRows)
	{
	if (dataGridView1.IsCurrentCellInEditMode)
	{
	e.Value = initialValue;
	}
	else
	{
	// Show a blank value if the cursor is just resting
	// on the last row.
	e.Value = String.Empty;
	}
	}
	else
	{
	e.Value = e.RowIndex;
	}
	}
	private void dataGridView1_CellValuePushed(object sender, DataGridViewCellValueEventArgs e)
	{
	store.Add(e.RowIndex, int.Parse(e.Value.ToString()));
	}
	#endregion
	private Dictionary<int, int> store = new Dictionary<int, int>();
	private void dataGridView1_CellValidating(object sender, DataGridViewCellValidatingEventArgs e)
	{
	dataGridView1.Rows[e.RowIndex].ErrorText = "";
	int newInteger;
	// Don't try to validate the 'new row' until finished
	// editing since there
	// is not any point in validating its initial value.
	if (dataGridView1.Rows[e.RowIndex].IsNewRow) { return; }
	if (!int.TryParse(e.FormattedValue.ToString(), out newInteger) || newInteger < 0)
	{
	e.Cancel = true;
	dataGridView1.Rows[e.RowIndex].ErrorText = "the value must be a non-negative integer";
	}
	}
	}
	}

view raw DataGridView_VirtualMode_cell_level_commit_scope.cs hosted with ❤ by GitHub