Microsoft.NET

……………………………………………….Expertise in .NET Technologies

Read and write to file using ASP.NET (VB)

Posted by Ravi Varma Thumati on October 30, 2009

Reading and writing to the file content using ASP.NET 2.0 and VB.NET 2.0 is actually very simple.

First, you will need to import the System.IO namespace.

Imports System.IO;

The System.IO namespace contains types that allow reading and writing to files and data streams, and types that provide basic file and directory support. Using the class of File ,and DirectoryInfo at here.

Use the DirectoryInfo class for typical operations such as copying, moving, renaming, creating, and deleting directories.

Use the File class for typical operations such as creating, opening, deleting, appending, copying, moving, and renaming to files.

Use the ReadAllText method to opens a text file, reads all lines of the file, and then closes the file.

Use the WriteAllText method Creates a new file, writes the specified string to the file, and then closes the file. If the target file already exists, it is overwritten.

We use the buttonDisplay_Click event to display the file content and use the buttonSave_Click even to save as a file.

The code as follows.

Protected Sub buttonDisplay_Click(ByVal sender As Object, ByVal e As System.EventArgs)

Dim FilePath As String
FilePath = txtBoxInput.Text
If File.Exists(FilePath) Then

textBoxContents.Text = File.ReadAllText(FilePath)

Else

Response.Write(“<script language=’javascript’>window.alert(‘File not found’);</script>”)

Return
End If

End Sub

Protected Sub buttonSave_Click(ByVal sender As Object, ByVal e As System.EventArgs)

Dim Folder As New DirectoryInfo(textboxPath.Text)
If Folder.Exists Then

If textboxName.Text <> String.Empty Then

Dim FilePathSave As String = Folder.ToString() + textboxName.Text File.WriteAllText(FilePathSave, textBoxContents.Text)

Else
Response.Write(“<script language=’javascript’>window.alert(‘Please enter file name’);</script>”)
End If

Else

Response.Write(“<script language=’javascript’>window.alert(‘Folder not found’);</script>”)

End If

End Sub

 

The front ReadWriteTextCSharp.aspx page looks something like this:

<table width=”600″ border=”0″ align=”center” cellpadding=”5″ cellspacing=”1″ bgcolor=”#cccccc”>

<tr>

<td bgcolor=”#eeeeee”>
<fieldset>
<legend>ReadWriteTextCsharp</legend>
<div>
<asp:Label runat=”server” Text=”Enter path of file to be examined and click Display”></asp:Label><br />
<asp:TextBox runat=”server” Width=”451px”></asp:TextBox>
<asp:Button runat=”server” Text=”Display” /><br />
<fieldset>
<legend>Content of file</legend>
<asp:Label runat=”server” Text=”You can edit the content and save as a file.”></asp:Label><br />
<table>

<tr>

<td>
<asp:TextBox runat=”server” tabIndex=”0″ height=”200px” textMode=”MultiLine” width=”450px”></asp:TextBox>
</td>

</tr>

</table>
<fieldset>
<legend>Save as</legend>Path:
<asp:TextBox runat=”server” Width=”237px”></asp:TextBox>File name:
<asp:TextBox runat=”server” Width=”93px”></asp:TextBox>
<asp:Button runat=”server” Text=”Save As” Width=”66px” /></fieldset>
</fieldset>
</div>
</fieldset>
</td>

</tr>

</table>

The flow for the code behind page is as follows.

Imports System.IO

Partial Class ReadWriteTextVB

Inherits System.Web.UI.Page
Protected Sub buttonDisplay_Click(ByVal sender As Object, ByVal e As System.EventArgs)

Dim FilePath As String
FilePath = txtBoxInput.Text
If File.Exists(FilePath) Then

textBoxContents.Text = File.ReadAllText(FilePath)

Else

Response.Write(“<script language=’javascript’>window.alert(‘File not found’);</script>”)

Return
End If

End Sub

Protected Sub buttonSave_Click(ByVal sender As Object, ByVal e As System.EventArgs)

Dim Folder As New DirectoryInfo(textboxPath.Text)
If Folder.Exists Then

If textboxName.Text <> String.Empty Then

Dim FilePathSave As String = Folder.ToString() + textboxName.Text File.WriteAllText(FilePathSave, textBoxContents.Text)

Else
Response.Write(“<script language=’javascript’>window.alert(‘Please enter file name’);</script>”)
End If

Else

Response.Write(“<script language=’javascript’>window.alert(‘Folder not found’);</script>”)

End If

End Sub

End Class

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