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FileDialog.DefaultExt-Eigenschaft

 

Veröffentlicht: Oktober 2016

Ruft die Standarddateierweiterung ab oder legt diese fest.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

public string DefaultExt { get; set; }

Eigenschaftswert

Type: System.String

Die Standarddateinamenerweiterung. Die zurückgegebene Zeichenfolge enthält keinen Punkt. Der Standardwert ist eine leere Zeichenfolge („“).

When the user of your application specifies a file name without an extension, the T:System.Windows.Forms.FileDialog appends an extension to the file name. The extension that is used is determined by the P:System.Windows.Forms.FileDialog.Filter and P:System.Windows.Forms.FileDialog.DefaultExt properties. If a filter is selected in the T:System.Windows.Forms.FileDialog and the filter specifies an extension, then that extension is used. If the filter selected uses a wildcard in place of the extension, then the extension specified in the P:System.Windows.Forms.FileDialog.DefaultExt property is used.

The following code example demonstrates using the M:System.Windows.Forms.RichTextBox.SaveFile(System.String) and M:System.Windows.Forms.RichTextBox.LoadFile(System.String) methods with streams. It also demonstrates using the P:System.Windows.Forms.FileDialog.FileName, P:System.Windows.Forms.FileDialog.DefaultExt, P:System.Windows.Forms.SaveFileDialog.CreatePrompt, and P:System.Windows.Forms.SaveFileDialog.OverwritePrompt members.

This is a complete example that is ready to run when you copy it to your project.

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();
		}
	}
}

.NET Framework
Verfügbar seit 1.1
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