Panduan: Menerapkan Mode Virtual di Formulir Windows Kontrol DataGridView
Saat Anda ingin menampilkan data tabular dalam jumlah yang sangat besar dalam DataGridView kontrol, Anda dapat mengatur VirtualMode properti ke true
dan secara eksplisit mengelola interaksi kontrol dengan penyimpanan datanya. Ini memungkinkan Anda menyempurnakan performa kontrol dalam situasi ini.
Kontrol ini DataGridView menyediakan beberapa peristiwa yang dapat Anda tangani untuk berinteraksi dengan penyimpanan data kustom. Panduan ini memandu Anda melalui proses penerapan penanganan aktivitas ini. Contoh kode dalam topik ini menggunakan sumber data yang sangat sederhana untuk tujuan ilustrasi. Dalam pengaturan produksi, Anda biasanya hanya akan memuat baris yang perlu Anda tampilkan ke dalam cache, dan menangani DataGridView peristiwa untuk berinteraksi dengan dan memperbarui cache. Untuk informasi selengkapnya, lihat Menerapkan Mode Virtual dengan Pemuatan Data Just-In-Time di kontrol Formulir Windows DataGridView
Untuk menyalin kode dalam topik ini sebagai satu daftar, lihat Cara: Menerapkan Mode Virtual di kontrol Formulir Windows DataGridView.
Membuat Formulir
Untuk menerapkan mode virtual
Buat kelas yang berasal dari Form dan berisi DataGridView kontrol.
Kode berikut berisi beberapa inisialisasi dasar. Ini mendeklarasikan beberapa variabel yang akan digunakan dalam langkah-langkah selanjutnya, menyediakan
Main
metode, dan menyediakan tata letak formulir sederhana di konstruktor kelas.#using <System.Drawing.dll> #using <System.dll> #using <System.Windows.Forms.dll> using namespace System; using namespace System::Windows::Forms; public ref class Customer { private: String^ companyNameValue; String^ contactNameValue; public: Customer() { // Leave fields empty. } Customer( String^ companyName, String^ contactName ) { companyNameValue = companyName; contactNameValue = contactName; } property String^ CompanyName { String^ get() { return companyNameValue; } void set( String^ value ) { companyNameValue = value; } } property String^ ContactName { String^ get() { return contactNameValue; } void set( String^ value ) { contactNameValue = value; } } }; public ref class Form1: public Form { private: DataGridView^ dataGridView1; // Declare an ArrayList to serve as the data store. System::Collections::ArrayList^ customers; // Declare a Customer object to store data for a row being edited. 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. int rowInEdit; // Declare a variable to indicate the commit scope. // Set this value to false to use cell-level commit scope. bool rowScopeCommit; public: static void Main() { Application::Run( gcnew Form1 ); } Form1() { dataGridView1 = gcnew DataGridView; customers = gcnew System::Collections::ArrayList; rowInEdit = -1; rowScopeCommit = true; // Initialize the form. this->dataGridView1->Dock = DockStyle::Fill; this->Controls->Add( this->dataGridView1 ); this->Load += gcnew EventHandler( this, &Form1::Form1_Load ); } private:
using System; using System.Windows.Forms; public class Form1 : Form { private DataGridView dataGridView1 = new DataGridView(); // Declare an ArrayList to serve as the data store. private System.Collections.ArrayList customers = new System.Collections.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; [STAThreadAttribute()] public static void Main() { Application.Run(new Form1()); } public Form1() { // 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)"; }
Imports System.Windows.Forms Public Class Form1 Inherits Form Private WithEvents dataGridView1 As New DataGridView() ' Declare an ArrayList to serve as the data store. Private customers As New System.Collections.ArrayList() ' Declare a Customer object to store data for a row being edited. Private customerInEdit As Customer ' 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 rowInEdit As Integer = -1 ' Declare a variable to indicate the commit scope. ' Set this value to false to use cell-level commit scope. Private rowScopeCommit As Boolean = True <STAThreadAttribute()> _ Public Shared Sub Main() Application.Run(New Form1()) End Sub Public Sub New() ' Initialize the form. Me.dataGridView1.Dock = DockStyle.Fill Me.Controls.Add(Me.dataGridView1) Me.Text = "DataGridView virtual-mode demo (row-level commit scope)" End Sub
}; int main() { Form1::Main(); }
}
End Class
Terapkan handler untuk peristiwa formulir Load Anda yang menginisialisasi DataGridView kontrol dan mengisi penyimpanan data dengan nilai sampel.
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 += gcnew DataGridViewCellValueEventHandler( this, &Form1::dataGridView1_CellValueNeeded ); this->dataGridView1->CellValuePushed += gcnew DataGridViewCellValueEventHandler( this, &Form1::dataGridView1_CellValuePushed ); this->dataGridView1->NewRowNeeded += gcnew DataGridViewRowEventHandler( this, &Form1::dataGridView1_NewRowNeeded ); this->dataGridView1->RowValidated += gcnew DataGridViewCellEventHandler( this, &Form1::dataGridView1_RowValidated ); this->dataGridView1->RowDirtyStateNeeded += gcnew QuestionEventHandler( this, &Form1::dataGridView1_RowDirtyStateNeeded ); this->dataGridView1->CancelRowEdit += gcnew QuestionEventHandler( this, &Form1::dataGridView1_CancelRowEdit ); this->dataGridView1->UserDeletingRow += gcnew DataGridViewRowCancelEventHandler( this, &Form1::dataGridView1_UserDeletingRow ); // Add columns to the DataGridView. DataGridViewTextBoxColumn^ companyNameColumn = gcnew DataGridViewTextBoxColumn; companyNameColumn->HeaderText = L"Company Name"; companyNameColumn->Name = L"Company Name"; DataGridViewTextBoxColumn^ contactNameColumn = gcnew DataGridViewTextBoxColumn; contactNameColumn->HeaderText = L"Contact Name"; contactNameColumn->Name = L"Contact Name"; this->dataGridView1->Columns->Add( companyNameColumn ); this->dataGridView1->Columns->Add( contactNameColumn ); this->dataGridView1->AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode::DisplayedCells; // Add some sample entries to the data store. this->customers->Add( gcnew Customer( L"Bon app'",L"Laurence Lebihan" ) ); this->customers->Add( gcnew Customer( L"Bottom-Dollar Markets",L"Elizabeth Lincoln" ) ); this->customers->Add( gcnew Customer( L"B's Beverages",L"Victoria Ashworth" ) ); // Set the row count, including the row for new records. this->dataGridView1->RowCount = 4; }
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.DisplayedCells; // 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 Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) _ Handles Me.Load ' Enable virtual mode. Me.dataGridView1.VirtualMode = True ' Add columns to the DataGridView. Dim companyNameColumn As New DataGridViewTextBoxColumn() With companyNameColumn .HeaderText = "Company Name" .Name = "Company Name" End With Dim contactNameColumn As New DataGridViewTextBoxColumn() With contactNameColumn .HeaderText = "Contact Name" .Name = "Contact Name" End With Me.dataGridView1.Columns.Add(companyNameColumn) Me.dataGridView1.Columns.Add(contactNameColumn) Me.dataGridView1.AutoSizeColumnsMode = _ DataGridViewAutoSizeColumnsMode.DisplayedCells ' Add some sample entries to the data store. Me.customers.Add(New Customer("Bon app'", "Laurence Lebihan")) Me.customers.Add(New Customer("Bottom-Dollar Markets", _ "Elizabeth Lincoln")) Me.customers.Add(New Customer("B's Beverages", "Victoria Ashworth")) ' Set the row count, including the row for new records. Me.dataGridView1.RowCount = 4 End Sub
Terapkan handler untuk CellValueNeeded peristiwa yang mengambil nilai sel yang diminta dari penyimpanan data atau objek yang
Customer
saat ini sedang diedit.Peristiwa ini terjadi setiap kali DataGridView kontrol perlu melukis sel.
void dataGridView1_CellValueNeeded( Object^ /*sender*/, System::Windows::Forms::DataGridViewCellValueEventArgs^ e ) { Customer^ customerTmp = nullptr; // Store a reference to the Customer object for the row being painted. if ( e->RowIndex == rowInEdit ) { customerTmp = this->customerInEdit; } else { customerTmp = dynamic_cast<Customer^>(this->customers[ e->RowIndex ]); } // Set the cell value to paint using the Customer object retrieved. int switchcase = 0; if ( (this->dataGridView1->Columns[ e->ColumnIndex ]->Name)->Equals( L"Company Name" ) ) switchcase = 1; else if ( (this->dataGridView1->Columns[ e->ColumnIndex ]->Name)->Equals( L"Contact Name" ) ) switchcase = 2; switch ( switchcase ) { case 1: e->Value = customerTmp->CompanyName; break; case 2: e->Value = customerTmp->ContactName; break; } }
private void dataGridView1_CellValueNeeded(object sender, System.Windows.Forms.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; } }
Private Sub dataGridView1_CellValueNeeded(ByVal sender As Object, _ ByVal e As System.Windows.Forms.DataGridViewCellValueEventArgs) _ Handles dataGridView1.CellValueNeeded ' If this is the row for new records, no values are needed. If e.RowIndex = Me.dataGridView1.RowCount - 1 Then Return End If Dim customerTmp As Customer = Nothing ' Store a reference to the Customer object for the row being painted. If e.RowIndex = rowInEdit Then customerTmp = Me.customerInEdit Else customerTmp = CType(Me.customers(e.RowIndex), Customer) End If ' Set the cell value to paint using the Customer object retrieved. Select Case Me.dataGridView1.Columns(e.ColumnIndex).Name Case "Company Name" e.Value = customerTmp.CompanyName Case "Contact Name" e.Value = customerTmp.ContactName End Select End Sub
Terapkan handler untuk CellValuePushed peristiwa yang menyimpan nilai sel yang diedit dalam objek yang
Customer
mewakili baris yang diedit. Kejadian ini terjadi setiap kali pengguna menerapkan perubahan nilai sel.void dataGridView1_CellValuePushed( Object^ /*sender*/, System::Windows::Forms::DataGridViewCellValueEventArgs^ e ) { Customer^ customerTmp = nullptr; // 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. if ( this->customerInEdit == nullptr ) { this->customerInEdit = gcnew Customer( (dynamic_cast<Customer^>(this->customers[ e->RowIndex ]))->CompanyName, (dynamic_cast<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. int switchcase = 0; if ( (this->dataGridView1->Columns[ e->ColumnIndex ]->Name)->Equals( L"Company Name" ) ) switchcase = 1; else if ( (this->dataGridView1->Columns[ e->ColumnIndex ]->Name)->Equals( L"Contact Name" ) ) switchcase = 2; switch ( switchcase ) { case 1: customerTmp->CompanyName = dynamic_cast<String^>(e->Value); break; case 2: customerTmp->ContactName = dynamic_cast<String^>(e->Value); break; } }
private void dataGridView1_CellValuePushed(object sender, System.Windows.Forms.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; } }
Private Sub dataGridView1_CellValuePushed(ByVal sender As Object, _ ByVal e As System.Windows.Forms.DataGridViewCellValueEventArgs) _ Handles dataGridView1.CellValuePushed Dim customerTmp As Customer = Nothing ' Store a reference to the Customer object for the row being edited. If e.RowIndex < Me.customers.Count Then ' If the user is editing a new row, create a new Customer object. If Me.customerInEdit Is Nothing Then Me.customerInEdit = New Customer( _ CType(Me.customers(e.RowIndex), Customer).CompanyName, _ CType(Me.customers(e.RowIndex), Customer).ContactName) End If customerTmp = Me.customerInEdit Me.rowInEdit = e.RowIndex Else customerTmp = Me.customerInEdit End If ' Set the appropriate Customer property to the cell value entered. Dim newValue As String = TryCast(e.Value, String) Select Case Me.dataGridView1.Columns(e.ColumnIndex).Name Case "Company Name" customerTmp.CompanyName = newValue Case "Contact Name" customerTmp.ContactName = newValue End Select End Sub
Terapkan handler untuk NewRowNeeded peristiwa yang membuat objek baru
Customer
yang mewakili baris yang baru dibuat.Kejadian ini terjadi setiap kali pengguna memasukkan baris untuk rekaman baru.
void dataGridView1_NewRowNeeded( Object^ /*sender*/, System::Windows::Forms::DataGridViewRowEventArgs^ /*e*/ ) { // Create a new Customer object when the user edits // the row for new records. this->customerInEdit = gcnew Customer; this->rowInEdit = this->dataGridView1->Rows->Count - 1; }
private void dataGridView1_NewRowNeeded(object sender, System.Windows.Forms.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; }
Private Sub dataGridView1_NewRowNeeded(ByVal sender As Object, _ ByVal e As System.Windows.Forms.DataGridViewRowEventArgs) _ Handles dataGridView1.NewRowNeeded ' Create a new Customer object when the user edits ' the row for new records. Me.customerInEdit = New Customer() Me.rowInEdit = Me.dataGridView1.Rows.Count - 1 End Sub
Terapkan handler untuk RowValidated peristiwa yang menyimpan baris baru atau yang dimodifikasi ke penyimpanan data.
Kejadian ini terjadi setiap kali pengguna mengubah baris saat ini.
void dataGridView1_RowValidated( Object^ /*sender*/, System::Windows::Forms::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 = nullptr; this->rowInEdit = -1; } else if ( this->customerInEdit != nullptr && e->RowIndex < this->customers->Count ) { // Save the modified Customer object in the data store. this->customers[ e->RowIndex ] = this->customerInEdit; this->customerInEdit = nullptr; this->rowInEdit = -1; } else if ( this->dataGridView1->ContainsFocus ) { this->customerInEdit = nullptr; this->rowInEdit = -1; } }
private void dataGridView1_RowValidated(object sender, System.Windows.Forms.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 Sub dataGridView1_RowValidated(ByVal sender As Object, _ ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) _ Handles dataGridView1.RowValidated ' Save row changes if any were made and release the edited ' Customer object if there is one. If e.RowIndex >= Me.customers.Count AndAlso _ e.RowIndex <> Me.dataGridView1.Rows.Count - 1 Then ' Add the new Customer object to the data store. Me.customers.Add(Me.customerInEdit) Me.customerInEdit = Nothing Me.rowInEdit = -1 ElseIf (Me.customerInEdit IsNot Nothing) AndAlso _ e.RowIndex < Me.customers.Count Then ' Save the modified Customer object in the data store. Me.customers(e.RowIndex) = Me.customerInEdit Me.customerInEdit = Nothing Me.rowInEdit = -1 ElseIf Me.dataGridView1.ContainsFocus Then Me.customerInEdit = Nothing Me.rowInEdit = -1 End If End Sub
Terapkan handler untuk RowDirtyStateNeeded peristiwa yang menunjukkan apakah CancelRowEdit peristiwa akan terjadi ketika pengguna memberi sinyal pembalikan baris dengan menekan ESC dua kali dalam mode edit atau sekali di luar mode edit.
Secara default, CancelRowEdit terjadi saat pembalikan baris ketika sel apa pun di baris saat ini telah dimodifikasi kecuali QuestionEventArgs.Response properti diatur ke
true
dalam RowDirtyStateNeeded penanganan aktivitas. Kejadian ini berguna ketika cakupan penerapan ditentukan pada waktu proses.void dataGridView1_RowDirtyStateNeeded( Object^ /*sender*/, System::Windows::Forms::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_RowDirtyStateNeeded(object sender, System.Windows.Forms.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 Sub dataGridView1_RowDirtyStateNeeded(ByVal sender As Object, _ ByVal e As System.Windows.Forms.QuestionEventArgs) _ Handles dataGridView1.RowDirtyStateNeeded If Not rowScopeCommit Then ' In cell-level commit scope, indicate whether the value ' of the current cell has been modified. e.Response = Me.dataGridView1.IsCurrentCellDirty End If End Sub
Terapkan handler untuk CancelRowEdit peristiwa yang membuang nilai objek yang
Customer
mewakili baris saat ini.Peristiwa ini terjadi ketika pengguna memberi sinyal pembalikan baris dengan menekan ESC dua kali dalam mode edit atau sekali di luar mode edit. Kejadian ini tidak terjadi jika tidak ada sel dalam baris saat ini yang telah dimodifikasi atau jika nilai QuestionEventArgs.Response properti telah diatur ke
false
dalam RowDirtyStateNeeded penanganan aktivitas.void dataGridView1_CancelRowEdit( Object^ /*sender*/, System::Windows::Forms::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 = gcnew Customer; } else { // If the user has canceled the edit of an existing row, // release the corresponding Customer object. this->customerInEdit = nullptr; this->rowInEdit = -1; } }
private void dataGridView1_CancelRowEdit(object sender, System.Windows.Forms.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 Sub dataGridView1_CancelRowEdit(ByVal sender As Object, _ ByVal e As System.Windows.Forms.QuestionEventArgs) _ Handles dataGridView1.CancelRowEdit If Me.rowInEdit = Me.dataGridView1.Rows.Count - 2 AndAlso _ Me.rowInEdit = Me.customers.Count Then ' If the user has canceled the edit of a newly created row, ' replace the corresponding Customer object with a new, empty one. Me.customerInEdit = New Customer() Else ' If the user has canceled the edit of an existing row, ' release the corresponding Customer object. Me.customerInEdit = Nothing Me.rowInEdit = -1 End If End Sub
Terapkan handler untuk UserDeletingRow peristiwa yang menghapus objek yang ada
Customer
dari penyimpanan data atau membuang objek yang belum disimpanCustomer
yang mewakili baris yang baru dibuat.Kejadian ini terjadi setiap kali pengguna menghapus baris dengan mengklik header baris dan menekan tombol DELETE.
void dataGridView1_UserDeletingRow( Object^ /*sender*/, System::Windows::Forms::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 = nullptr; } }
private void dataGridView1_UserDeletingRow(object sender, System.Windows.Forms.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 Sub dataGridView1_UserDeletingRow(ByVal sender As Object, _ ByVal e As System.Windows.Forms.DataGridViewRowCancelEventArgs) _ Handles dataGridView1.UserDeletingRow If e.Row.Index < Me.customers.Count Then ' If the user has deleted an existing row, remove the ' corresponding Customer object from the data store. Me.customers.RemoveAt(e.Row.Index) End If If e.Row.Index = Me.rowInEdit Then ' If the user has deleted a newly created row, release ' the corresponding Customer object. Me.rowInEdit = -1 Me.customerInEdit = Nothing End If End Sub
Terapkan kelas sederhana
Customers
untuk mewakili item data yang digunakan oleh contoh kode ini.public ref class Customer { private: String^ companyNameValue; String^ contactNameValue; public: Customer() { // Leave fields empty. } Customer( String^ companyName, String^ contactName ) { companyNameValue = companyName; contactNameValue = contactName; } property String^ CompanyName { String^ get() { return companyNameValue; } void set( String^ value ) { companyNameValue = value; } } property String^ ContactName { String^ get() { return contactNameValue; } void set( String^ value ) { contactNameValue = value; } } };
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; } } }
Public Class Customer Private companyNameValue As String Private contactNameValue As String Public Sub New() ' Leave fields empty. End Sub Public Sub New(ByVal companyName As String, ByVal contactName As String) companyNameValue = companyName contactNameValue = contactName End Sub Public Property CompanyName() As String Get Return companyNameValue End Get Set(ByVal value As String) companyNameValue = value End Set End Property Public Property ContactName() As String Get Return contactNameValue End Get Set(ByVal value As String) contactNameValue = value End Set End Property End Class
Menguji Aplikasi
Anda sekarang dapat menguji formulir untuk memastikan formulir tersebut berulah seperti yang diharapkan.
Untuk menguji formulir
Kompilasi dan jalankan aplikasi.
Anda akan melihat kontrol yang DataGridView diisi dengan tiga catatan pelanggan. Anda dapat mengubah nilai beberapa sel dalam baris dan menekan ESC dua kali dalam mode edit dan sekali di luar mode edit untuk mengembalikan seluruh baris ke nilai aslinya. Saat Anda mengubah, menambahkan, atau menghapus baris dalam kontrol,
Customer
objek di penyimpanan data juga dimodifikasi, ditambahkan, atau dihapus.
Langkah berikutnya
Aplikasi ini memberi Anda pemahaman dasar tentang peristiwa yang harus Anda tangani untuk menerapkan mode virtual dalam DataGridView kontrol. Anda dapat meningkatkan aplikasi dasar ini dengan sejumlah cara:
Terapkan penyimpanan data yang menyimpan nilai dari database eksternal. Cache harus mengambil dan membuang nilai seperlunya sehingga hanya berisi apa yang diperlukan untuk ditampilkan saat mengonsumsi sejumlah kecil memori di komputer klien.
Menyempurnakan performa penyimpanan data tergantung pada kebutuhan Anda. Misalnya, Anda mungkin ingin mengkompensasi koneksi jaringan yang lambat daripada batasan memori komputer klien dengan menggunakan ukuran cache yang lebih besar dan meminimalkan jumlah kueri database.
Untuk informasi selengkapnya tentang penembolokan nilai dari database eksternal, lihat Cara: Menerapkan Mode Virtual dengan Pemuatan Data Just-In-Time di Formulir Windows Kontrol DataGridView.
Baca juga
- DataGridView
- VirtualMode
- CellValueNeeded
- CellValuePushed
- NewRowNeeded
- RowValidated
- RowDirtyStateNeeded
- CancelRowEdit
- UserDeletingRow
- Penyetelan Performa di Kontrol Formulir Windows DataGridView
- Praktik Terbaik untuk Menskalakan Kontrol Formulir Windows DataGridView
- Menerapkan Mode Virtual dengan Pemuatan Data Just-In-Time di Formulir Windows Kontrol DataGridView
- Cara: Menerapkan Mode Virtual di Formulir Windows Kontrol DataGridView
.NET Desktop feedback
Saran dan Komentar
https://aka.ms/ContentUserFeedback.
Segera hadir: Sepanjang tahun 2024 kami akan menghentikan penggunaan GitHub Issues sebagai mekanisme umpan balik untuk konten dan menggantinya dengan sistem umpan balik baru. Untuk mengetahui informasi selengkapnya, lihat:Kirim dan lihat umpan balik untuk