FileDialog.DefaultExt 屬性
定義
重要
部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。
取得或設定預設的副檔名。
public:
property System::String ^ DefaultExt { System::String ^ get(); void set(System::String ^ value); };public string DefaultExt { get; set; }member this.DefaultExt : string with get, setPublic Property DefaultExt As String屬性值
預設的副檔名。 傳回的字串不包含句號。 預設值為空字串 ("")。
範例
下列程式碼範例示範如何搭配資料流程使用 RichTextBox.SaveFile 和 RichTextBox.LoadFile 方法。 它也會示範如何使用 FileName 、 DefaultExt 、 SaveFileDialog.CreatePrompt 和 SaveFileDialog.OverwritePrompt 成員。
這是當您將它複製到專案時所要執行的完整範例。
using namespace System;
using namespace System::Drawing;
using namespace System::IO;
using namespace System::Windows::Forms;
public ref class Form1: public Form
{
public private:
RichTextBox^ RichTextBox1;
Button^ Button1;
RichTextBox^ RichTextBox2;
Button^ Button2;
SaveFileDialog^ SaveFileDialog1;
public:
Form1()
: Form()
{
userInput = gcnew MemoryStream;
this->RichTextBox1 = gcnew RichTextBox;
this->Button1 = gcnew Button;
this->RichTextBox2 = gcnew RichTextBox;
this->Button2 = gcnew Button;
this->SaveFileDialog1 = gcnew SaveFileDialog;
this->SuspendLayout();
this->RichTextBox1->Location = Point( 24, 64 );
this->RichTextBox1->Name = "RichTextBox1";
this->RichTextBox1->TabIndex = 0;
this->RichTextBox1->Text = "Type something here.";
this->Button1->Location = Point( 96, 16 );
this->Button1->Name = "Button1";
this->Button1->Size = Size( 96, 24 );
this->Button1->TabIndex = 1;
this->Button1->Text = "Save To Stream";
this->Button1->Click +=
gcnew EventHandler( this, &Form1::Button1_Click );
this->RichTextBox2->Location = Point( 152, 64 );
this->RichTextBox2->Name = "RichTextBox2";
this->RichTextBox2->TabIndex = 3;
this->RichTextBox2->Text = "It will be added to the stream "
"and appear here.";
this->Button2->Location = Point( 104, 200 );
this->Button2->Name = "Button2";
this->Button2->Size = Size( 88, 32 );
this->Button2->TabIndex = 4;
this->Button2->Text = "Save Stream To File";
this->Button2->Click +=
gcnew EventHandler( this, &Form1::Button2_Click );
this->ClientSize = Size( 292, 266 );
this->Controls->Add( this->Button2 );
this->Controls->Add( this->RichTextBox2 );
this->Controls->Add( this->Button1 );
this->Controls->Add( this->RichTextBox1 );
this->Name = "Form1";
this->Text = "Form1";
this->ResumeLayout( false );
}
// Declare a new memory stream.
MemoryStream^ userInput;
private:
// Save the content of RichTextBox1 to the memory stream,
// appending a LineFeed character.
void Button1_Click( Object^ /*sender*/, EventArgs^ /*e*/ )
{
RichTextBox1->SaveFile( userInput, RichTextBoxStreamType::PlainText );
userInput->WriteByte( 13 );
// Display the entire contents of the stream,
// by setting its position to 0, to RichTextBox2.
userInput->Position = 0;
RichTextBox2->LoadFile( userInput, RichTextBoxStreamType::PlainText );
}
// Shows the use of a SaveFileDialog to save a MemoryStream to a file.
void Button2_Click( Object^ /*sender*/, EventArgs^ /*e*/ )
{
// Set the properties on SaveFileDialog1 so the user is
// prompted to create the file if it doesn't exist
// or overwrite the file if it does exist.
SaveFileDialog1->CreatePrompt = true;
SaveFileDialog1->OverwritePrompt = true;
// Set the file name to myText.txt, set the type filter
// to text files, and set the initial directory to the
// MyDocuments folder.
SaveFileDialog1->FileName = "myText";
// DefaultExt is only used when "All files" is selected from
// the filter box and no extension is specified by the user.
SaveFileDialog1->DefaultExt = "txt";
SaveFileDialog1->Filter = "Text files (*.txt)|*.txt|All files (*.*)|*.*";
SaveFileDialog1->InitialDirectory =
Environment->GetFolderPath(Environment::SpecialFolder::MyDocuments);
// Call ShowDialog and check for a return value of DialogResult.OK,
// which indicates that the file was saved.
DialogResult result = SaveFileDialog1->ShowDialog();
Stream^ fileStream;
if ( result == DialogResult::OK )
{
fileStream = SaveFileDialog1->OpenFile();
userInput->Position = 0;
userInput->WriteTo( fileStream );
fileStream->Close();
}
}
};
int main()
{
Application::Run( gcnew Form1 );
}
using System;
using System.Drawing;
using System.IO;
using System.Windows.Forms;
public partial class Form1: Form
{
internal RichTextBox RichTextBox1;
internal Button Button1;
internal RichTextBox RichTextBox2;
internal Button Button2;
internal SaveFileDialog SaveFileDialog1;
public Form1() : base()
{
this.RichTextBox1 = new RichTextBox();
this.Button1 = new Button();
this.RichTextBox2 = new RichTextBox();
this.Button2 = new Button();
this.SaveFileDialog1 = new SaveFileDialog();
this.SuspendLayout();
this.RichTextBox1.Location = new Point(24, 64);
this.RichTextBox1.Name = "RichTextBox1";
this.RichTextBox1.TabIndex = 0;
this.RichTextBox1.Text = "Type something here.";
this.Button1.Location = new Point(96, 16);
this.Button1.Name = "Button1";
this.Button1.Size = new Size(96, 24);
this.Button1.TabIndex = 1;
this.Button1.Text = "Save To Stream";
this.Button1.Click += new EventHandler(Button1_Click);
this.RichTextBox2.Location = new Point(152, 64);
this.RichTextBox2.Name = "RichTextBox2";
this.RichTextBox2.TabIndex = 3;
this.RichTextBox2.Text =
"It will be added to the stream and appear here.";
this.Button2.Location = new Point(104, 200);
this.Button2.Name = "Button2";
this.Button2.Size = new Size(88, 32);
this.Button2.TabIndex = 4;
this.Button2.Text = "Save Stream To File";
this.Button2.Click += new EventHandler(Button2_Click);
this.ClientSize = new Size(292, 266);
this.Controls.Add(this.Button2);
this.Controls.Add(this.RichTextBox2);
this.Controls.Add(this.Button1);
this.Controls.Add(this.RichTextBox1);
this.Name = "Form1";
this.Text = "Form1";
this.ResumeLayout(false);
}
public static void Main()
{
Application.Run(new Form1());
}
// Declare a new memory stream.
MemoryStream userInput = new MemoryStream();
// Save the content of RichTextBox1 to the memory stream,
// appending a LineFeed character.
private void Button1_Click(Object sender, EventArgs e)
{
RichTextBox1.SaveFile(userInput, RichTextBoxStreamType.PlainText);
userInput.WriteByte(13);
// Display the entire contents of the stream,
// by setting its position to 0, to RichTextBox2.
userInput.Position = 0;
RichTextBox2.LoadFile(userInput, RichTextBoxStreamType.PlainText);
}
// Shows the use of a SaveFileDialog to save a MemoryStream to a file.
private void Button2_Click(Object sender, EventArgs e)
{
// Set the properties on SaveFileDialog1 so the user is
// prompted to create the file if it doesn't exist
// or overwrite the file if it does exist.
SaveFileDialog1.CreatePrompt = true;
SaveFileDialog1.OverwritePrompt = true;
// Set the file name to myText.txt, set the type filter
// to text files, and set the initial directory to the
// MyDocuments folder.
SaveFileDialog1.FileName = "myText";
// DefaultExt is only used when "All files" is selected from
// the filter box and no extension is specified by the user.
SaveFileDialog1.DefaultExt = "txt";
SaveFileDialog1.Filter =
"Text files (*.txt)|*.txt|All files (*.*)|*.*";
SaveFileDialog1.InitialDirectory =
Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
// Call ShowDialog and check for a return value of DialogResult.OK,
// which indicates that the file was saved.
DialogResult result = SaveFileDialog1.ShowDialog();
Stream fileStream;
if (result == DialogResult.OK)
{
// Open the file, copy the contents of memoryStream to fileStream,
// and close fileStream. Set the memoryStream.Position value to 0
// to copy the entire stream.
fileStream = SaveFileDialog1.OpenFile();
userInput.Position = 0;
userInput.WriteTo(fileStream);
fileStream.Close();
}
}
}
Imports System.Drawing
Imports System.IO
Imports System.Windows.Forms
Partial Public Class Form1
Inherits Form
Friend WithEvents RichTextBox1 As RichTextBox
Friend WithEvents Button1 As Button
Friend WithEvents RichTextBox2 As RichTextBox
Friend WithEvents Button2 As Button
Friend WithEvents SaveFileDialog1 As SaveFileDialog
Public Sub New()
MyBase.New()
Me.RichTextBox1 = New RichTextBox
Me.Button1 = New Button
Me.RichTextBox2 = New RichTextBox
Me.Button2 = New Button
Me.SaveFileDialog1 = New SaveFileDialog
Me.SuspendLayout()
Me.RichTextBox1.Location = New Point(24, 64)
Me.RichTextBox1.Name = "RichTextBox1"
Me.RichTextBox1.TabIndex = 0
Me.RichTextBox1.Text = "Type something here."
Me.Button1.Location = New Point(96, 16)
Me.Button1.Name = "Button1"
Me.Button1.Size = New Size(96, 24)
Me.Button1.TabIndex = 1
Me.Button1.Text = "Save To Stream"
Me.RichTextBox2.Location = New Point(152, 64)
Me.RichTextBox2.Name = "RichTextBox2"
Me.RichTextBox2.TabIndex = 3
Me.RichTextBox2.Text = "It will be added to the stream and appear here."
Me.Button2.Location = New Point(104, 200)
Me.Button2.Name = "Button2"
Me.Button2.Size = New Size(88, 32)
Me.Button2.TabIndex = 4
Me.Button2.Text = "Save Stream To File"
Me.ClientSize = New Size(292, 266)
Me.Controls.Add(Me.Button2)
Me.Controls.Add(Me.RichTextBox2)
Me.Controls.Add(Me.Button1)
Me.Controls.Add(Me.RichTextBox1)
Me.Name = "Form1"
Me.Text = "Form1"
Me.ResumeLayout(False)
End Sub
Public Shared Sub Main()
Application.Run(New Form1)
End Sub
' Declare a new memory stream.
Dim userInput As New MemoryStream
' Save the content of RichTextBox1 to the memory stream, appending
'a LineFeed character.
Private Sub Button1_Click(ByVal sender As Object, _
ByVal e As EventArgs) Handles Button1.Click
RichTextBox1.SaveFile(userInput, RichTextBoxStreamType.PlainText)
userInput.WriteByte(13)
' Display the entire contents of the stream,
' by setting its position to 0, to RichTextBox2.
userInput.Position = 0
RichTextBox2.LoadFile(userInput, RichTextBoxStreamType.PlainText)
End Sub
' Shows the use of a SaveFileDialog to save a MemoryStream to a file.
Private Sub Button2_Click(ByVal sender As Object, _
ByVal e As EventArgs) Handles Button2.Click
' Set the properties on SaveFileDialog1 so the user is
' prompted to create the file if it doesn't exist
' or overwrite the file if it does exist.
SaveFileDialog1.CreatePrompt = True
SaveFileDialog1.OverwritePrompt = True
' Set the file name to myText.txt, set the type filter
' to text files, and set the initial directory to the
' MyDocuments folder.
SaveFileDialog1.FileName = "myText"
' DefaultExt is only used when "All files" is selected from
' the filter box and no extension is specified by the user.
SaveFileDialog1.DefaultExt = "txt"
SaveFileDialog1.Filter = "Text files (*.txt)|*.txt|All files (*.*)|*.*"
SaveFileDialog1.InitialDirectory = _
Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)
' Call ShowDialog and check for a return value of DialogResult.OK,
' which indicates that the file was saved.
Dim result As DialogResult = SaveFileDialog1.ShowDialog()
Dim fileStream As Stream
If (result = DialogResult.OK) Then
' Open the file, copy the contents of memoryStream to fileStream,
' and close fileStream. Set the memoryStream.Position value to 0 to
' copy the entire stream.
fileStream = SaveFileDialog1.OpenFile()
userInput.Position = 0
userInput.WriteTo(fileStream)
fileStream.Close()
End If
End Sub
End Class
備註
當應用程式的使用者指定沒有副檔名的檔案名時，會將 FileDialog 副檔名附加至檔案名。 使用的延伸模組是由 Filter 和 DefaultExt 屬性所決定。 如果在 中 FileDialog 選取篩選準則，且篩選準則指定延伸模組，則會使用該延伸模組。 如果選取的篩選使用萬用字元取代延伸模組，則會使用 屬性中指定的 DefaultExt 延伸模組。
