Cómo: Agregar capacidades de búsqueda a un control ListView
A menudo al trabajar con una lista grande de elementos en un control ListView, se desea ofrecer funciones de búsqueda al usuario. El control ListView proporciona esta función de dos maneras diferentes: la coincidencia de texto y la búsqueda de ubicación.
El método FindItemWithText permite realizar una búsqueda de texto en ListView en una vista de lista o de detalles, proporcionando una cadena de búsqueda y un índice inicial y final opcional. Por el contrario, el método FindNearestItem permite encontrar un elemento en ListView en una vista en icono o en mosaico, proporcionando un conjunto de coordenadas x e y y una dirección para buscar.
Para encontrar un elemento utilizando el texto
Cree un ListView con la propiedad View establecida en Details o List y, a continuación, rellene ListView con elementos.
Llame al método FindItemWithText, pasando el texto del elemento que le gustaría buscar.
En el ejemplo de código siguiente se muestra cómo crear un ListView básico, cómo rellenarlo con elementos y cómo utilizar la entrada de texto por el usuario para buscar un elemento en la lista.
Private textListView As New ListView()
Private WithEvents searchBox As New TextBox()
Private Sub InitializeTextSearchListView()
searchBox.Location = New Point(150, 20)
textListView.Scrollable = True
textListView.Width = 80
textListView.Height = 50
' Set the View to list to use the FindItemWithText method.
textListView.View = View.List
' Populate the ListView with items.
textListView.Items.AddRange(New ListViewItem() { _
New ListViewItem("Amy Alberts"), _
New ListViewItem("Amy Recker"), _
New ListViewItem("Erin Hagens"), _
New ListViewItem("Barry Johnson"), _
New ListViewItem("Jay Hamlin"), _
New ListViewItem("Brian Valentine"), _
New ListViewItem("Brian Welker"), _
New ListViewItem("Daniel Weisman")})
' Add the controls to the form.
Me.Controls.Add(textListView)
Me.Controls.Add(searchBox)
End Sub
Private Sub searchBox_TextChanged(ByVal sender As Object, ByVal e As EventArgs) _
Handles searchBox.TextChanged
' Call FindItemWithText with the contents of the textbox.
Dim foundItem As ListViewItem = _
textListView.FindItemWithText(searchBox.Text, False, 0, True)
If (foundItem IsNot Nothing) Then
textListView.TopItem = foundItem
End If
End Sub
private ListView textListView = new ListView();
private TextBox searchBox = new TextBox();
private void InitializeTextSearchListView()
{
searchBox.Location = new Point(10, 60);
textListView.Scrollable = true;
textListView.Width = 80;
textListView.Height = 50;
// Set the View to list to use the FindItemWithText method.
textListView.View = View.List;
// Populate the ListViewWithItems
textListView.Items.AddRange(new ListViewItem[]{
new ListViewItem("Amy Alberts"),
new ListViewItem("Amy Recker"),
new ListViewItem("Erin Hagens"),
new ListViewItem("Barry Johnson"),
new ListViewItem("Jay Hamlin"),
new ListViewItem("Brian Valentine"),
new ListViewItem("Brian Welker"),
new ListViewItem("Daniel Weisman") });
// Handle the TextChanged to get the text for our search.
searchBox.TextChanged += new EventHandler(searchBox_TextChanged);
// Add the controls to the form.
this.Controls.Add(textListView);
this.Controls.Add(searchBox);
}
private void searchBox_TextChanged(object sender, EventArgs e)
{
// Call FindItemWithText with the contents of the textbox.
ListViewItem foundItem =
textListView.FindItemWithText(searchBox.Text, false, 0, true);
if (foundItem != null)
{
textListView.TopItem = foundItem;
}
}
private:
ListView^ textListView;
TextBox^ searchBox;
private:
void InitializeTextSearchListView()
{
textListView = gcnew ListView();
searchBox = gcnew TextBox();
searchBox->Location = Point(150, 20);
textListView->Scrollable = true;
textListView->Width = 100;
// Set the View to list to use the FindItemWithText method.
textListView->View = View::List;
// Populate the ListViewWithItems
textListView->Items->AddRange(gcnew array<ListViewItem^>{
gcnew ListViewItem("Amy Alberts"),
gcnew ListViewItem("Amy Recker"),
gcnew ListViewItem("Erin Hagens"),
gcnew ListViewItem("Barry Johnson"),
gcnew ListViewItem("Jay Hamlin"),
gcnew ListViewItem("Brian Valentine"),
gcnew ListViewItem("Brian Welker"),
gcnew ListViewItem("Daniel Weisman") });
// Handle the TextChanged to get the text for our search.
searchBox->TextChanged += gcnew EventHandler(this,
&Form1::searchBox_TextChanged);
// Add the controls to the form.
this->Controls->Add(textListView);
this->Controls->Add(searchBox);
}
private:
void searchBox_TextChanged(Object^ sender, EventArgs^ e)
{
// Call FindItemWithText with the contents of the textbox.
ListViewItem^ foundItem =
textListView->FindItemWithText(searchBox->Text, false, 0, true);
if (foundItem != nullptr)
{
textListView->TopItem = foundItem;
}
}
Para buscar un elemento mediante las coordenadas x e y
Cree un ListView con la propiedad View establecida en SmallIcon o LargeIcon y, a continuación, rellene ListView con elementos.
Llame al método FindNearestItem, pasando las coordenadas x e y deseadas, así como la dirección en la que desea buscar.
En el ejemplo de código siguiente se muestra cómo crear un ListView de icono básico, cómo rellenarlo con elementos y cómo capturar el evento MouseDown para buscar el elemento más cercano en una búsqueda hacia arriba.
Private WithEvents iconListView As New ListView()
Private previousItemBox As New TextBox()
Private Sub InitializeLocationSearchListView()
previousItemBox.Location = New Point(150, 20)
' Create an image list for the icon ListView.
iconListView.LargeImageList = New ImageList()
' Add an image to the ListView large icon list.
iconListView.LargeImageList.Images.Add(New Bitmap(GetType(Control), "Edit.bmp"))
' Set the view to large icon and add some items with the image
' in the image list.
iconListView.View = View.SmallIcon
iconListView.Items.AddRange(New ListViewItem() { _
New ListViewItem("Amy Alberts", 0), _
New ListViewItem("Amy Recker", 0), _
New ListViewItem("Erin Hagens", 0), _
New ListViewItem("Barry Johnson", 0), _
New ListViewItem("Jay Hamlin", 0), _
New ListViewItem("Brian Valentine", 0), _
New ListViewItem("Brian Welker", 0), _
New ListViewItem("Daniel Weisman", 0)})
Me.Controls.Add(iconListView)
Me.Controls.Add(previousItemBox)
End Sub
Sub iconListView_MouseDown(ByVal sender As Object, ByVal e As MouseEventArgs) _
Handles iconListView.MouseDown
' Find the next item up from where the user clicked.
Dim foundItem As ListViewItem = _
iconListView.FindNearestItem(SearchDirectionHint.Up, e.X, e.Y)
' Display the results in a textbox.
If (foundItem IsNot Nothing) Then
previousItemBox.Text = foundItem.Text
Else
previousItemBox.Text = "No item found"
End If
End Sub
ListView iconListView = new ListView();
TextBox previousItemBox = new TextBox();
private void InitializeLocationSearchListView()
{
previousItemBox.Location = new Point(150, 20);
// Create an image list for the icon ListView.
iconListView.LargeImageList = new ImageList();
iconListView.Height = 400;
// Add an image to the ListView large icon list.
iconListView.LargeImageList.Images.Add(
new Bitmap(typeof(Control), "Edit.bmp"));
// Set the view to large icon and add some items with the image
// in the image list.
iconListView.View = View.LargeIcon;
iconListView.Items.AddRange(new ListViewItem[]{
new ListViewItem("Amy Alberts", 0),
new ListViewItem("Amy Recker", 0),
new ListViewItem("Erin Hagens", 0),
new ListViewItem("Barry Johnson", 0),
new ListViewItem("Jay Hamlin", 0),
new ListViewItem("Brian Valentine", 0),
new ListViewItem("Brian Welker", 0),
new ListViewItem("Daniel Weisman", 0) });
this.Controls.Add(iconListView);
this.Controls.Add(previousItemBox);
// Handle the MouseDown event to capture user input.
iconListView.MouseDown +=
new MouseEventHandler(iconListView_MouseDown);
//iconListView.MouseWheel += new MouseEventHandler(iconListView_MouseWheel);
}
void iconListView_MouseDown(object sender, MouseEventArgs e)
{
// Find the an item above where the user clicked.
ListViewItem foundItem =
iconListView.FindNearestItem(SearchDirectionHint.Up, e.X, e.Y);
// Display the results in a textbox..
if (foundItem != null)
previousItemBox.Text = foundItem.Text;
else
previousItemBox.Text = "No item found";
}
ListView^ iconListView;
TextBox^ previousItemBox;
private:
void InitializeLocationSearchListView()
{
previousItemBox = gcnew TextBox();
iconListView = gcnew ListView();
previousItemBox->Location = Point(150, 20);
// Create an image list for the icon ListView.
iconListView->SmallImageList = gcnew ImageList();
// Add an image to the ListView small icon list.
iconListView->SmallImageList->Images->Add(
gcnew Bitmap(Control::typeid, "Edit.bmp"));
// Set the view to small icon and add some items with the image
// in the image list.
iconListView->View = View::SmallIcon;
iconListView->Items->AddRange(gcnew array<ListViewItem^>{
gcnew ListViewItem("Amy Alberts", 0),
gcnew ListViewItem("Amy Recker", 0),
gcnew ListViewItem("Erin Hagens", 0),
gcnew ListViewItem("Barry Johnson", 0),
gcnew ListViewItem("Jay Hamlin", 0),
gcnew ListViewItem("Brian Valentine", 0),
gcnew ListViewItem("Brian Welker", 0),
gcnew ListViewItem("Daniel Weisman", 0) });
this->Controls->Add(iconListView);
this->Controls->Add(previousItemBox);
// Handle the MouseDown event to capture user input.
iconListView->MouseDown += gcnew MouseEventHandler(
this, &Form1::iconListView_MouseDown);
}
void iconListView_MouseDown(Object^ sender, MouseEventArgs^ e)
{
// Find the next item up from where the user clicked.
ListViewItem^ foundItem = iconListView->FindNearestItem(
SearchDirectionHint::Up, e->X, e->Y);
// Display the results in a textbox..
if (foundItem != nullptr)
{
previousItemBox->Text = foundItem->Text;
}
else
{
previousItemBox->Text = "No item found";
}
}
Vea también
Tareas
Cómo: Agregar y quitar elementos con el control ListView de Windows Forms
Referencia
Información general del control ListView (Formularios Windows Forms)