DataGridView.SelectionChanged Událost
Definice
Důležité
Některé informace platí pro předběžně vydaný produkt, který se může zásadně změnit, než ho výrobce nebo autor vydá. Microsoft neposkytuje žádné záruky, výslovné ani předpokládané, týkající se zde uváděných informací.
Nastane při změně aktuálního výběru.
public:
event EventHandler ^ SelectionChanged;public event EventHandler SelectionChanged;public event EventHandler? SelectionChanged;member this.SelectionChanged : EventHandler Public Custom Event SelectionChanged As EventHandler Event Type
Příklady
Následující příklad kódu ukazuje použití této události. V příkladu formulář zobrazí součet hodnot ve vybraných buňkách a při změně výběru součet aktualizuje.
using System;
using System.Drawing;
using System.Windows.Forms;
public class Form1 : Form
{
private DataGridView DataGridView1 = new DataGridView();
private FlowLayoutPanel FlowLayoutPanel1 = new FlowLayoutPanel();
private Label Label1 = new Label();
private Label Label2 = new Label();
private Label Label3 = new Label();
private Label Label4 = new Label();
// Establish the main entry point for the application.
[STAThreadAttribute()]
public static void Main()
{
Application.Run(new Form1());
}
public Form1()
{
// Initialize the form.
// This code can be replaced with designer generated code.
AutoSize = true;
// Set the FlowLayoutPanel1 properties.
FlowLayoutPanel1.FlowDirection = FlowDirection.TopDown;
FlowLayoutPanel1.Location = new System.Drawing.Point(354, 0);
FlowLayoutPanel1.AutoSize = true;
FlowLayoutPanel1.Controls.Add(Label1);
FlowLayoutPanel1.Controls.Add(Label2);
FlowLayoutPanel1.Controls.Add(Label3);
FlowLayoutPanel1.Controls.Add(Label4);
Controls.Add(FlowLayoutPanel1);
Controls.Add(DataGridView1);
// Set the Label properties.
Label1.AutoSize = true;
Label2.AutoSize = true;
Label3.AutoSize = true;
}
protected override void OnLoad(EventArgs e)
{
PopulateDataGridView();
UpdateLabelText();
UpdateBalance();
DataGridView1.CellValidating += new
DataGridViewCellValidatingEventHandler(
DataGridView1_CellValidating);
DataGridView1.CellValidated += new DataGridViewCellEventHandler(
DataGridView1_CellValidated);
DataGridView1.CellValueChanged += new DataGridViewCellEventHandler(
DataGridView1_CellValueChanged);
DataGridView1.RowsRemoved += new DataGridViewRowsRemovedEventHandler(
DataGridView1_RowsRemoved);
DataGridView1.SelectionChanged += new EventHandler(
DataGridView1_SelectionChanged);
DataGridView1.UserAddedRow += new DataGridViewRowEventHandler(
DataGridView1_UserAddedRow);
DataGridView1.UserDeletingRow += new
DataGridViewRowCancelEventHandler(DataGridView1_UserDeletingRow);
base.OnLoad(e);
}
// Replace this with your own code to populate the DataGridView.
private void PopulateDataGridView()
{
DataGridView1.Size = new Size(350, 400);
DataGridView1.AllowUserToDeleteRows = true;
// Add columns to the DataGridView.
DataGridView1.ColumnCount = 4;
DataGridView1.SelectionMode =
DataGridViewSelectionMode.RowHeaderSelect;
// Set the properties of the DataGridView columns.
DataGridView1.Columns[0].Name = "Description";
DataGridView1.Columns[1].Name = "Withdrawals";
DataGridView1.Columns[2].Name = "Deposits";
DataGridView1.Columns[3].Name = "Balance";
DataGridView1.Columns["Description"].HeaderText = "Description";
DataGridView1.Columns["Withdrawals"].HeaderText = "W(-)";
DataGridView1.Columns["Deposits"].HeaderText = "D(+)";
DataGridView1.Columns["Balance"].HeaderText = "Balance";
DataGridView1.Columns["Balance"].ReadOnly = true;
DataGridView1.Columns["Description"].SortMode =
DataGridViewColumnSortMode.NotSortable;
DataGridView1.Columns["Withdrawals"].SortMode =
DataGridViewColumnSortMode.NotSortable;
DataGridView1.Columns["Deposits"].SortMode =
DataGridViewColumnSortMode.NotSortable;
DataGridView1.Columns["Balance"].SortMode =
DataGridViewColumnSortMode.NotSortable;
// Add rows of data to the DataGridView.
DataGridView1.Rows.Add(new string[] {
"Starting Balance", "", "", "1000" });
DataGridView1.Rows.Add(new string[] {
"Paycheck Deposit", "", "850", "" });
DataGridView1.Rows.Add(new string[] { "Rent", "-500", "", "" });
DataGridView1.Rows.Add(new string[] { "Groceries", "-25", "", "" });
DataGridView1.Rows.Add(new string[] { "Tax Return", "", "300", "" });
// Allow the user to edit the starting balance cell
DataGridView1.Rows[0].ReadOnly = true;
DataGridView1.Rows[0].Cells["Balance"].ReadOnly = false;
// Autosize the columns.
DataGridView1.AutoResizeColumns();
}
private void DataGridView1_CellValueChanged(
object sender, DataGridViewCellEventArgs e)
{
// Update the balance column whenever the value of any cell changes.
UpdateBalance();
}
private void DataGridView1_RowsRemoved(
object sender, DataGridViewRowsRemovedEventArgs e)
{
// Update the balance column whenever rows are deleted.
UpdateBalance();
}
private void UpdateBalance()
{
int counter;
int balance;
int deposit;
int withdrawal;
// Iterate through the rows, skipping the Starting Balance row.
for (counter = 1; counter < (DataGridView1.Rows.Count - 1);
counter++)
{
deposit = 0;
withdrawal = 0;
balance = int.Parse(DataGridView1.Rows[counter - 1]
.Cells["Balance"].Value.ToString());
if (DataGridView1.Rows[counter].Cells["Deposits"].Value != null)
{
// Verify that the cell value is not an empty string.
if (DataGridView1.Rows[counter]
.Cells["Deposits"].Value.ToString().Length != 0)
{
deposit = int.Parse(DataGridView1.Rows[counter]
.Cells["Deposits"].Value.ToString());
}
}
if (DataGridView1.Rows[counter].Cells["Withdrawals"].Value != null)
{
if (DataGridView1.Rows[counter]
.Cells["Withdrawals"].Value.ToString().Length != 0)
{
withdrawal = int.Parse(DataGridView1.Rows[counter]
.Cells["Withdrawals"].Value.ToString());
}
}
DataGridView1.Rows[counter].Cells["Balance"].Value =
(balance + deposit + withdrawal).ToString();
}
}
private void DataGridView1_SelectionChanged(object sender, EventArgs e)
{
// Update the labels to reflect changes to the selection.
UpdateLabelText();
}
private void DataGridView1_UserAddedRow(
object sender, DataGridViewRowEventArgs e)
{
// Update the labels to reflect changes to the number of entries.
UpdateLabelText();
}
private void UpdateLabelText()
{
int WithdrawalTotal = 0;
int DepositTotal = 0;
int SelectedCellTotal = 0;
int counter;
// Iterate through all the rows and sum up the appropriate columns.
for (counter = 0; counter < (DataGridView1.Rows.Count);
counter++)
{
if (DataGridView1.Rows[counter].Cells["Withdrawals"].Value
!= null)
{
if (DataGridView1.Rows[counter].
Cells["Withdrawals"].Value.ToString().Length != 0)
{
WithdrawalTotal += int.Parse(DataGridView1.Rows[counter].
Cells["Withdrawals"].Value.ToString());
}
}
if (DataGridView1.Rows[counter].Cells["Deposits"].Value != null)
{
if (DataGridView1.Rows[counter]
.Cells["Deposits"].Value.ToString().Length != 0)
{
DepositTotal += int.Parse(DataGridView1.Rows[counter]
.Cells["Deposits"].Value.ToString());
}
}
}
// Iterate through the SelectedCells collection and sum up the values.
for (counter = 0;
counter < (DataGridView1.SelectedCells.Count); counter++)
{
if (DataGridView1.SelectedCells[counter].FormattedValueType ==
Type.GetType("System.String"))
{
string value = null;
// If the cell contains a value that has not been commited,
// use the modified value.
if (DataGridView1.IsCurrentCellDirty == true)
{
value = DataGridView1.SelectedCells[counter]
.EditedFormattedValue.ToString();
}
else
{
value = DataGridView1.SelectedCells[counter]
.FormattedValue.ToString();
}
if (value != null)
{
// Ignore cells in the Description column.
if (DataGridView1.SelectedCells[counter].ColumnIndex !=
DataGridView1.Columns["Description"].Index)
{
if (value.Length != 0)
{
SelectedCellTotal += int.Parse(value);
}
}
}
}
}
// Set the labels to reflect the current state of the DataGridView.
Label1.Text = "Withdrawals Total: " + WithdrawalTotal.ToString();
Label2.Text = "Deposits Total: " + DepositTotal.ToString();
Label3.Text = "Selected Cells Total: " + SelectedCellTotal.ToString();
Label4.Text = "Total entries: " + DataGridView1.RowCount.ToString();
}
private void DataGridView1_CellValidating(object sender,
DataGridViewCellValidatingEventArgs e)
{
int testint;
if (e.ColumnIndex != 0)
{
if (e.FormattedValue.ToString().Length != 0)
{
// Try to convert the cell value to an int.
if (!int.TryParse(e.FormattedValue.ToString(), out testint))
{
DataGridView1.Rows[e.RowIndex].ErrorText =
"Error: Invalid entry";
e.Cancel = true;
}
}
}
}
private void DataGridView1_CellValidated(object sender,
DataGridViewCellEventArgs e)
{
// Clear any error messages that may have been set in cell validation.
DataGridView1.Rows[e.RowIndex].ErrorText = null;
}
private void DataGridView1_UserDeletingRow(object sender,
DataGridViewRowCancelEventArgs e)
{
DataGridViewRow startingBalanceRow = DataGridView1.Rows[0];
// Check if the Starting Balance row is included in the selected rows
if (DataGridView1.SelectedRows.Contains(startingBalanceRow))
{
// Do not allow the user to delete the Starting Balance row.
MessageBox.Show("Cannot delete Starting Balance row!");
// Cancel the deletion if the Starting Balance row is included.
e.Cancel = true;
}
}
}
Imports System.Drawing
Imports System.Windows.Forms
Public Class Form1
Inherits Form
Private WithEvents DataGridView1 As New DataGridView()
Private FlowLayoutPanel1 As New FlowLayoutPanel()
Private Label1 As New Label()
Private Label2 As New Label()
Private Label3 As New Label()
Private Label4 As New Label()
' Establish the main entry point for the application.
<STAThreadAttribute()> _
Public Shared Sub Main()
Application.Run(New Form1())
End Sub
Public Sub New()
' Set the FlowLayoutPanel1 properties.
With Me
.AutoSize = True
With .FlowLayoutPanel1
.FlowDirection = FlowDirection.TopDown
.Location = New System.Drawing.Point(354, 0)
.AutoSize = True
.Controls.Add(Label1)
.Controls.Add(Label2)
.Controls.Add(Label3)
.Controls.Add(Label4)
End With
.Controls.Add(Me.FlowLayoutPanel1)
.Controls.Add(DataGridView1)
' Set the Label properties.
.Label1.AutoSize = True
.Label2.AutoSize = True
.Label3.AutoSize = True
.PopulateDataGridView()
.UpdateLabelText()
.UpdateBalance()
End With
End Sub
' Replace this with your own code to populate the DataGridView.
Private Sub PopulateDataGridView()
With Me.DataGridView1
.Size = New Size(350, 400)
.AllowUserToDeleteRows = True
' Add columns to the DataGridView.
.ColumnCount = 4
.SelectionMode = DataGridViewSelectionMode.RowHeaderSelect
' Set the properties of the DataGridView columns.
.Columns(0).Name = "Description"
.Columns(1).Name = "Withdrawals"
.Columns(2).Name = "Deposits"
.Columns(3).Name = "Balance"
.Columns("Description").HeaderText = "Description"
.Columns("Withdrawals").HeaderText = "W(-)"
.Columns("Deposits").HeaderText = "D(+)"
.Columns("Balance").HeaderText = "Balance"
.Columns("Balance").ReadOnly = True
.Columns("Description").SortMode = _
DataGridViewColumnSortMode.NotSortable
.Columns("Withdrawals").SortMode = _
DataGridViewColumnSortMode.NotSortable
.Columns("Deposits").SortMode = _
DataGridViewColumnSortMode.NotSortable
.Columns("Balance").SortMode = _
DataGridViewColumnSortMode.NotSortable
End With
' Add rows of data to the DataGridView.
With Me.DataGridView1.Rows
.Add(New String() {"Starting Balance", "", "", "1000"})
.Add(New String() {"Paycheck Deposit", "", "850", ""})
.Add(New String() {"Rent", "-500", "", ""})
.Add(New String() {"Groceries", "-25", "", ""})
.Add(New String() {"Tax Return", "", "300", ""})
End With
' Allow the user to edit the starting balance cell
DataGridView1.Rows(0).ReadOnly = True
DataGridView1.Rows(0).Cells("Balance").ReadOnly = False
' Autosize the columns.
Me.DataGridView1.AutoResizeColumns()
End Sub
Private Sub CellValueChanged(ByVal sender As Object, _
ByVal e As DataGridViewCellEventArgs) _
Handles DataGridView1.CellValueChanged
' Update the balance column whenever the values of any cell changes.
UpdateBalance()
End Sub
Private Sub RowsRemoved(ByVal sender As Object, _
ByVal e As DataGridViewRowsRemovedEventArgs) _
Handles DataGridView1.RowsRemoved
' Update the balance column whenever rows are deleted.
UpdateBalance()
End Sub
Private Sub UpdateBalance()
Dim counter As Integer
Dim balance As Integer
Dim deposit As Integer
Dim withdrawal As Integer
' Iterate through the rows, skipping the Starting Balance Row.
For counter = 1 To (DataGridView1.Rows.Count - 2)
deposit = 0
withdrawal = 0
balance = Integer.Parse(DataGridView1.Rows(counter - 1) _
.Cells("Balance").Value.ToString())
If Not DataGridView1.Rows(counter) _
.Cells("Deposits").Value Is Nothing Then
' Verify that the cell value is not an empty string.
If Not DataGridView1.Rows(counter) _
.Cells("Deposits").Value.ToString().Length = 0 Then
deposit = Integer.Parse(DataGridView1.Rows(counter) _
.Cells("Deposits").Value.ToString())
End If
End If
If Not DataGridView1.Rows(counter) _
.Cells("Withdrawals").Value Is Nothing Then
If Not DataGridView1.Rows(counter) _
.Cells("Withdrawals").Value.ToString().Length = 0 Then
withdrawal = Integer.Parse(DataGridView1.Rows(counter) _
.Cells("Withdrawals").Value.ToString())
End If
End If
DataGridView1.Rows(counter).Cells("Balance").Value = _
(balance + deposit + withdrawal).ToString()
Next
End Sub
Private Sub SelectionChanged(ByVal sender As Object, _
ByVal e As EventArgs) Handles DataGridView1.SelectionChanged
' Update the labels to reflect changes to the selection.
UpdateLabelText()
End Sub
Private Sub UserAddedRow(ByVal sender As Object, _
ByVal e As DataGridViewRowEventArgs) _
Handles DataGridView1.UserAddedRow
' Update the labels to reflect changes to the number of entries.
UpdateLabelText()
End Sub
Private Sub UpdateLabelText()
Dim WithdrawalTotal As Integer = 0
Dim DepositTotal As Integer = 0
Dim SelectedCellTotal As Integer = 0
Dim counter As Integer
' Iterate through all the rows and sum up the appropriate columns.
For counter = 0 To (DataGridView1.Rows.Count - 1)
If Not DataGridView1.Rows(counter) _
.Cells("Withdrawals").Value Is Nothing Then
If Not DataGridView1.Rows(counter) _
.Cells("Withdrawals").Value.ToString().Length = 0 Then
WithdrawalTotal += _
Integer.Parse(DataGridView1.Rows(counter) _
.Cells("Withdrawals").Value.ToString())
End If
End If
If Not DataGridView1.Rows(counter) _
.Cells("Deposits").Value Is Nothing Then
If Not DataGridView1.Rows(counter) _
.Cells("Deposits").Value.ToString().Length = 0 Then
DepositTotal += _
Integer.Parse(DataGridView1.Rows(counter) _
.Cells("Deposits").Value.ToString())
End If
End If
Next
' Iterate through the SelectedCells collection and sum up the values.
For counter = 0 To (DataGridView1.SelectedCells.Count - 1)
If DataGridView1.SelectedCells(counter).FormattedValueType Is _
Type.GetType("System.String") Then
Dim value As String = Nothing
' If the cell contains a value that has not been commited,
' use the modified value.
If (DataGridView1.IsCurrentCellDirty = True) Then
value = DataGridView1.SelectedCells(counter) _
.EditedFormattedValue.ToString()
Else
value = DataGridView1.SelectedCells(counter) _
.FormattedValue.ToString()
End If
If value IsNot Nothing Then
' Ignore cells in the Description column.
If Not DataGridView1.SelectedCells(counter).ColumnIndex = _
DataGridView1.Columns("Description").Index Then
If Not value.Length = 0 Then
SelectedCellTotal += Integer.Parse(value)
End If
End If
End If
End If
Next
' Set the labels to reflect the current state of the DataGridView.
Label1.Text = "Withdrawals Total: " & WithdrawalTotal.ToString()
Label2.Text = "Deposits Total: " & DepositTotal.ToString()
Label3.Text = "Selected Cells Total: " & SelectedCellTotal.ToString()
Label4.Text = "Total entries: " & DataGridView1.RowCount.ToString()
End Sub
Private Sub CellValidating(ByVal sender As Object, _
ByVal e As DataGridViewCellValidatingEventArgs) _
Handles DataGridView1.CellValidating
Dim testInteger As Integer
If Not e.ColumnIndex = 0 Then
If Not e.FormattedValue.ToString().Length = 0 Then
' Try to convert the cell value to an Integer.
If Not Integer.TryParse(e.FormattedValue.ToString(), _
testInteger) Then
DataGridView1.Rows(e.RowIndex).ErrorText = _
"Error: Invalid entry"
e.Cancel = True
End If
End If
End If
End Sub
Private Sub CellValidated(ByVal sender As Object, _
ByVal e As DataGridViewCellEventArgs) _
Handles DataGridView1.CellValidated
' Clear any error messages that may have been set in cell validation.
DataGridView1.Rows(e.RowIndex).ErrorText = Nothing
End Sub
Private Sub UserDeletingRow(ByVal sender As Object, _
ByVal e As DataGridViewRowCancelEventArgs) _
Handles DataGridView1.UserDeletingRow
Dim startingBalanceRow As DataGridViewRow = DataGridView1.Rows(0)
' Check if the starting balance row is included in the selected rows
If DataGridView1.SelectedRows.Contains(startingBalanceRow) Then
' Do not allow the user to delete the Starting Balance row.
MessageBox.Show("Cannot delete Starting Balance row!")
' Cancel the deletion if the Starting Balance row is included.
e.Cancel = True
End If
End Sub
End Class
Poznámky
K této události dochází při výběru buněk nebo zrušení výběru, ať už prostřednictvím kódu programu nebo akce uživatele. Tato událost je například užitečná, když chcete zobrazit součet aktuálně vybraných buněk.
Když změníte hodnotu CurrentCell vlastnosti, SelectionChanged událost nastane před událostí CurrentCellChanged . Jakákoli SelectionChanged obslužná rutina události, která v tuto chvíli přistupuje k CurrentCell vlastnosti, získá předchozí hodnotu.
Další informace o zpracování událostí najdete v tématu Zpracování a vyvolávání událostí.
Platí pro
Viz také
Spolupracujte s námi na GitHubu
Zdroj tohoto obsahu najdete na GitHubu, kde můžete také vytvářet a kontrolovat problémy a žádosti o přijetí změn. Další informace najdete v našem průvodci pro přispěvatele.
