FileDialog.DefaultExt プロパティとは何？わかりやすく解説 Weblio辞書

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.NET Framework クラスライブラリリファレンス

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FileDialog.DefaultExt プロパティ

既定のファイル名の拡張子を取得または設定します。

名前空間: System.Windows.Forms
アセンブリ: System.Windows.Forms (system.windows.forms.dll 内)
構文

Visual Basic (宣言)

Public Property DefaultExt As
 String

Visual Basic (使用法)

Dim instance As FileDialog
Dim value As String

value = instance.DefaultExt

instance.DefaultExt = value

public string DefaultExt { get;
 set; }

C++

public:
property String^ DefaultExt {
    String^ get ();
    void set (String^ value);
}

/** @property */
public String get_DefaultExt ()

/** @property */
public void set_DefaultExt (String value)

JScript

public function get DefaultExt
 () : String

public function set DefaultExt
 (value : String)

プロパティ値
既定のファイル名の拡張子。返される文字列にはピリオドが含まれません。既定値は空の文字列 ("") です。

使用例

RichTextBox.SaveFile メソッドと RichTextBox.LoadFile メソッドをストリームと一緒に使用するコード例を次に示します。また、この例では、FileName メンバ、DefaultExt メンバ、SaveFileDialog.CreatePrompt メンバ、および SaveFileDialog.OverwritePrompt メンバも使用しています。

これは完成された例であるため、プロジェクトにコピーすると実行できます。

Visual Basic

Imports System.Windows.Forms

Public Class Form1
    Inherits System.Windows.Forms.Form

    Friend WithEvents RichTextBox1 As
 System.Windows.Forms.RichTextBox
    Friend WithEvents Button1 As
 System.Windows.Forms.Button
    Friend WithEvents RichTextBox2 As
 System.Windows.Forms.RichTextBox
    Friend WithEvents Button2 As
 System.Windows.Forms.Button
    Friend WithEvents SaveFileDialog1 As
 System.Windows.Forms.SaveFileDialog

    Public Sub New()
        MyBase.New()
        Me.RichTextBox1 = New System.Windows.Forms.RichTextBox
        Me.Button1 = New System.Windows.Forms.Button
        Me.RichTextBox2 = New System.Windows.Forms.RichTextBox
        Me.Button2 = New System.Windows.Forms.Button
        Me.SaveFileDialog1 = New System.Windows.Forms.SaveFileDialog
        Me.SuspendLayout()
        Me.RichTextBox1.Location = New System.Drawing.Point(24,
 64)
        Me.RichTextBox1.Name = "RichTextBox1"
        Me.RichTextBox1.TabIndex = 0
        Me.RichTextBox1.Text = "Type something
 here."
        Me.Button1.Location = New System.Drawing.Point(96,
 16)
        Me.Button1.Name = "Button1"
        Me.Button1.Size = New System.Drawing.Size(96,
 24)
        Me.Button1.TabIndex = 1
        Me.Button1.Text = "Save To Stream"
        Me.RichTextBox2.Location = New System.Drawing.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 System.Drawing.Point(104,
 200)
        Me.Button2.Name = "Button2"
        Me.Button2.Size = New System.Drawing.Size(88,
 32)
        Me.Button2.TabIndex = 4
        Me.Button2.Text = "Save Stream To File"
        Me.ClientSize = New System.Drawing.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
 System.IO.MemoryStream

    ' Save the content of RichTextBox1 to the memory stream, appending
    'a LineFeed character.  
    Private Sub Button1_Click(ByVal
 sender As System.Object, _
        ByVal e As System.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 System.Object, _
        ByVal e As System.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 drive C.
        SaveFileDialog1.FileName = "myText"
        SaveFileDialog1.DefaultExt = "txt"
        SaveFileDialog1.Filter = "Text files (*.txt)|*.txt"
        SaveFileDialog1.InitialDirectory = "c:\"

        ' 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 System.IO.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

using System.Windows.Forms;



public class Form1:
    System.Windows.Forms.Form

{
    
    internal System.Windows.Forms.RichTextBox RichTextBox1;
    internal System.Windows.Forms.Button Button1;
    internal System.Windows.Forms.RichTextBox RichTextBox2;
    internal System.Windows.Forms.Button Button2;
    internal System.Windows.Forms.SaveFileDialog SaveFileDialog1;

    public Form1() : base()
    {   
        
        this.RichTextBox1 = new System.Windows.Forms.RichTextBox();
        this.Button1 = new System.Windows.Forms.Button();
        this.RichTextBox2 = new System.Windows.Forms.RichTextBox();
        this.Button2 = new System.Windows.Forms.Button();
        this.SaveFileDialog1 = new System.Windows.Forms.SaveFileDialog();
        this.SuspendLayout();
        this.RichTextBox1.Location = new System.Drawing.Point(24,
 64);
        this.RichTextBox1.Name = "RichTextBox1";
        this.RichTextBox1.TabIndex = 0;
        this.RichTextBox1.Text = "Type something here.";
        this.Button1.Location = new System.Drawing.Point(96,
 16);
        this.Button1.Name = "Button1";
        this.Button1.Size = new System.Drawing.Size(96,
 24);
        this.Button1.TabIndex = 1;
        this.Button1.Text = "Save To Stream";
        this.Button1.Click += new System.EventHandler(Button1_Click);
        this.RichTextBox2.Location = new System.Drawing.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 System.Drawing.Point(104,
 200);
        this.Button2.Name = "Button2";
        this.Button2.Size = new System.Drawing.Size(88,
 32);
        this.Button2.TabIndex = 4;
        this.Button2.Text = "Save Stream To File";
        this.Button2.Click += new System.EventHandler(Button2_Click);
        this.ClientSize = new System.Drawing.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.
    System.IO.MemoryStream userInput = new System.IO.MemoryStream();

    // Save the content of RichTextBox1 to the memory stream, 
    // appending a LineFeed character.  
    private void Button1_Click(System.Object
 sender, 
        System.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(System.Object
 sender, System.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 drive C.
        SaveFileDialog1.FileName = "myText";
        SaveFileDialog1.DefaultExt = "txt";
        SaveFileDialog1.Filter = "Text files (*.txt)|*.txt";
        SaveFileDialog1.InitialDirectory = "c:\\";

        // Call ShowDialog and check for a return value of DialogResult.OK
,
        // which indicates that the file was saved. 
        DialogResult result = SaveFileDialog1.ShowDialog();
        System.IO.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();
        }
    }
}

C++

using namespace System::Windows::Forms;
public ref class Form1: public
 System::Windows::Forms::Form
{
public private:
   System::Windows::Forms::RichTextBox^ RichTextBox1;
   System::Windows::Forms::Button^ Button1;
   System::Windows::Forms::RichTextBox^ RichTextBox2;
   System::Windows::Forms::Button^ Button2;
   System::Windows::Forms::SaveFileDialog^ SaveFileDialog1;

public:
   Form1()
      : Form()
   {
      userInput = gcnew System::IO::MemoryStream;
      this->RichTextBox1 = gcnew System::Windows::Forms::RichTextBox;
      this->Button1 = gcnew System::Windows::Forms::Button;
      this->RichTextBox2 = gcnew System::Windows::Forms::RichTextBox;
      this->Button2 = gcnew System::Windows::Forms::Button;
      this->SaveFileDialog1 = gcnew System::Windows::Forms::SaveFileDialog;
      this->SuspendLayout();
      this->RichTextBox1->Location = System::Drawing::Point(
 24, 64 );
      this->RichTextBox1->Name = "RichTextBox1";
      this->RichTextBox1->TabIndex = 0;
      this->RichTextBox1->Text = "Type something here.";
      this->Button1->Location = System::Drawing::Point(
 96, 16 );
      this->Button1->Name = "Button1";
      this->Button1->Size = System::Drawing::Size( 96, 24
 );
      this->Button1->TabIndex = 1;
      this->Button1->Text = "Save To Stream";
      this->Button1->Click += gcnew System::EventHandler(
 this, &Form1::Button1_Click );
      this->RichTextBox2->Location = System::Drawing::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 = System::Drawing::Point(
 104, 200 );
      this->Button2->Name = "Button2";
      this->Button2->Size = System::Drawing::Size( 88, 32
 );
      this->Button2->TabIndex = 4;
      this->Button2->Text = "Save Stream To File";
      this->Button2->Click += gcnew System::EventHandler(
 this, &Form1::Button2_Click );
      this->ClientSize = System::Drawing::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.
   System::IO::MemoryStream^ userInput;

private:

   // Save the content of RichTextBox1 to the memory stream, 
   // appending a LineFeed character.  
   void Button1_Click( System::Object^ /*sender*/, System::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( System::Object^ /*sender*/, System::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 drive C.
      SaveFileDialog1->FileName = "myText";
      SaveFileDialog1->DefaultExt = "txt";
      SaveFileDialog1->Filter = "Text files (*.txt)|*.txt";
      SaveFileDialog1->InitialDirectory = "c:\\";
      
      // Call ShowDialog and check for a return value of DialogResult.OK
,
      // which indicates that the file was saved. 
      System::Windows::Forms::DialogResult result = SaveFileDialog1->ShowDialog();
      System::IO::Stream^ fileStream;
      if ( result == ::DialogResult::OK )
      {
         fileStream = SaveFileDialog1->OpenFile();
         userInput->Position = 0;
         userInput->WriteTo( fileStream );
         fileStream->Close();
      }
   }

};

int main()
{
   Application::Run( gcnew Form1 );
}

import System.Windows.Forms.*;

public class Form1 extends System.Windows.Forms.Form
{
    System.Windows.Forms.RichTextBox richTextBox1;
    System.Windows.Forms.Button button1;
    System.Windows.Forms.RichTextBox richTextBox2;
    System.Windows.Forms.Button button2;
    System.Windows.Forms.SaveFileDialog saveFileDialog1;

    public Form1()
    {
        super();
        this.richTextBox1 = new System.Windows.Forms.RichTextBox();
        this.button1 = new System.Windows.Forms.Button();
        this.richTextBox2 = new System.Windows.Forms.RichTextBox();
        this.button2 = new System.Windows.Forms.Button();
        this.saveFileDialog1 = new System.Windows.Forms.SaveFileDialog();
        this.SuspendLayout();
        this.richTextBox1.set_Location(new
 System.Drawing.Point(24, 64));
        this.richTextBox1.set_Name("RichTextBox1");
        this.richTextBox1.set_TabIndex(0);
        this.richTextBox1.set_Text("Type something here.");
        this.button1.set_Location(new System.Drawing.Point(96,
 16));
        this.button1.set_Name("Button1");
        this.button1.set_Size(new System.Drawing.Size(96,
 24));
        this.button1.set_TabIndex(1);
        this.button1.set_Text("Save To Stream");
        this.button1.add_Click(new System.EventHandler(button1_Click));
        this.richTextBox2.set_Location(new
 System.Drawing.Point(152, 64));
        this.richTextBox2.set_Name("RichTextBox2");
        this.richTextBox2.set_TabIndex(3);
        this.richTextBox2.set_Text("It will be added to the
 stream "
            + "and appear here.");
        this.button2.set_Location(new System.Drawing.Point(104,
 200));
        this.button2.set_Name("Button2");
        this.button2.set_Size(new System.Drawing.Size(88,
 32));
        this.button2.set_TabIndex(4);
        this.button2.set_Text("Save Stream To File");
        this.button2.add_Click(new System.EventHandler(button2_Click));
        this.set_ClientSize(new System.Drawing.Size(292,
 266));
        this.get_Controls().Add(this.button2);
        this.get_Controls().Add(this.richTextBox2);
        this.get_Controls().Add(this.button1);
        this.get_Controls().Add(this.richTextBox1);
        this.set_Name("Form1");
        this.set_Text("Form1");
        this.ResumeLayout(false);
    } //Form1

    public static void main(String[]
 args)
    {
        Application.Run(new Form1());
    } //main

    // Declare a new memory stream.
    private System.IO.MemoryStream userInput = new
 System.IO.MemoryStream();

    // Save the content of RichTextBox1 to the memory stream, 
    // appending a LineFeed character.  
    private void button1_Click(Object sender,
 System.EventArgs e)
    {
        richTextBox1.SaveFile(userInput, RichTextBoxStreamType.PlainText);
        userInput.WriteByte(System.Convert.ToByte(13));
        // Display the entire contents of the stream,
        // by setting its position to 0, to RichTextBox2.
        userInput.set_Position(0);
        richTextBox2.LoadFile(userInput, RichTextBoxStreamType.PlainText);
    } //button1_Click

    // Shows the use of a SaveFileDialog to save a MemoryStream to a
 file.
    private void button2_Click(Object sender,
 System.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.set_CreatePrompt(true);
        saveFileDialog1.set_OverwritePrompt(true);
        // Set the file name to myText.txt, set the type filter
        // to text files, and set the initial directory to drive C.
        saveFileDialog1.set_FileName("myText");
        saveFileDialog1.set_DefaultExt("txt");
        saveFileDialog1.set_Filter("Text files (*.txt)|*.txt");
        saveFileDialog1.set_InitialDirectory("c:\\");
        // Call ShowDialog and check for a return value of DialogResult.OK
,
        // which indicates that the file was saved. 
        DialogResult result = saveFileDialog1.ShowDialog();
        System.IO.Stream fileStream;

        if (result.Equals(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.set_Position(0);
            userInput.WriteTo(fileStream);
            fileStream.Close();
        }
    } //button2_Click
} //Form1

プラットフォーム

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0

参照

関連項目
FileDialog クラス
FileDialog メンバ
System.Windows.Forms 名前空間

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FileDialog.DefaultExt プロパティとは？ わかりやすく解説

FileDialog.DefaultExt プロパティ

FileDialog.DefaultExt プロパティとは？わかりやすく解説