Fix Visual Basic file reading examples: remove hardcoded paths, add RichTextBox support, and include project file (#48474)

* Initial plan

* Fix file path handling and add RichTextBox examples for Visual Basic file reading

Co-authored-by: BillWagner <[email protected]>

* Add VbFileIORead.vbproj for CI build

Co-authored-by: BillWagner <[email protected]>

* Update samples/snippets/visualbasic/VS_Snippets_VBCSharp/VbFileIORead/VB/VbFileIORead.vbproj

Co-authored-by: Genevieve Warren <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: BillWagner <[email protected]>
Co-authored-by: Bill Wagner <[email protected]>
Co-authored-by: Genevieve Warren <[email protected]>

Author: 3 people

docs/visual-basic/developing-apps/programming/drives-directories-files/how-to-read-from-text-files.md

@@ -31,6 +31,19 @@ Use the `ReadAllText` method of the `My.Computer.FileSystem` object to read the
 
 [!code-vb[VbFileIORead#3](~/samples/snippets/visualbasic/VS_Snippets_VBCSharp/VbFileIORead/VB/Class1.vb#3)]
 
+### To read from a text file into a RichTextBox control
+
+To load the contents of a text file directly into a RichTextBox control, read the file contents into a string and assign it to the `Text` property of the RichTextBox. The following example shows how to read a text file and load it into a RichTextBox control.
+
+[!code-vb[VbFileIORead#21](~/samples/snippets/visualbasic/VS_Snippets_VBCSharp/VbFileIORead/VB/Class1.vb#21)]
+
+For better error handling and file path management, you can use the following approach that constructs a proper file path and handles potential exceptions. This approach avoids hardcoded drive paths that can cause issues on different systems:
+
+[!code-vb[VbFileIORead#22](~/samples/snippets/visualbasic/VS_Snippets_VBCSharp/VbFileIORead/VB/Class1.vb#22)]
+
+> [!NOTE]
+> When specifying file paths, avoid using hardcoded absolute paths like "C:\temp\file.txt" as these can cause issues on systems where the drive letter or directory structure is different. Instead, use relative paths or construct paths using <xref:System.IO.Path.Combine%2A> to ensure your code works across different environments.
+
 ## Robust Programming
 
 The following conditions may cause an exception:

samples/snippets/visualbasic/VS_Snippets_VBCSharp/VbFileIORead/VB/Class1.vb

@@ -20,20 +20,45 @@ Class Class735fe9d70f7a4185ba02f35e580ec4b8
     Public Sub Method2()
         ' <snippet2>
         Dim fileReader As String
-        fileReader = My.Computer.FileSystem.ReadAllText("C:\test.txt")
+        fileReader = My.Computer.FileSystem.ReadAllText("test.txt")
         MsgBox(fileReader)
         ' </snippet2>
     End Sub
 
     Public Sub Method3()
         ' <snippet3>
         Dim fileReader As String
-        fileReader = My.Computer.FileSystem.ReadAllText("C:\test.txt",
+        fileReader = My.Computer.FileSystem.ReadAllText("test.txt",
            System.Text.Encoding.UTF32)
         MsgBox(fileReader)
         ' </snippet3>
     End Sub
 
+    Public Sub LoadTextIntoRichTextBox()
+        ' <snippet21>
+        ' Load text file into a RichTextBox control
+        ' Note: This assumes RichTextBox1 is a control on your form
+        Dim fileText As String
+        fileText = My.Computer.FileSystem.ReadAllText("test.txt")
+        ' RichTextBox1.Text = fileText
+        ' </snippet21>
+    End Sub
+
+    Public Sub LoadTextIntoRichTextBoxWithPath()
+        ' <snippet22>
+        ' Load text file into a RichTextBox control using a specific path
+        Try
+            Dim filePath As String = System.IO.Path.Combine(System.AppDomain.CurrentDomain.BaseDirectory, "test.txt")
+            Dim fileText As String = My.Computer.FileSystem.ReadAllText(filePath)
+            ' RichTextBox1.Text = fileText
+        Catch ex As System.IO.FileNotFoundException
+            MsgBox("File not found: " & ex.Message)
+        Catch ex As Exception
+            MsgBox("Error reading file: " & ex.Message)
+        End Try
+        ' </snippet22>
+    End Sub
+
 End Class
 
 Class Class8d185eb279ca42cd95a7d3ff44a5a0f8

samples/snippets/visualbasic/VS_Snippets_VBCSharp/VbFileIORead/VB/VbFileIORead.vbproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net4.81</TargetFramework>
+  </PropertyGroup>
+
+</Project>

samples/snippets/visualbasic/VS_Snippets_VBCSharp/VbFileIORead/VB/test.txt

@@ -0,0 +1,3 @@
+This is a sample text file for testing the file reading examples.
+It contains multiple lines of text that can be read into a string variable
+or loaded directly into a RichTextBox control.