TextFieldParser.ReadFields Method

Reference

Definition

Namespace:: Microsoft.VisualBasic.FileIO

Assembly:: Microsoft.VisualBasic.Core.dll

Assembly:: Microsoft.VisualBasic.dll

Source:: TextFieldParser.vb

Source:: TextFieldParser.vb

Source:: TextFieldParser.vb

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Reads all fields on the current line, returns them as an array of strings, and advances the cursor to the next line containing data.

public:
 cli::array <System::String ^> ^ ReadFields();

public string[]? ReadFields ();

public string[] ReadFields ();

member this.ReadFields : unit -> string[]

Public Function ReadFields () As String()

Returns

String[]

An array of strings that contains field values for the current line.

Exceptions

MalformedLineException

A field cannot be parsed by using the specified format.

Examples

This example uses the ReadFields method to read from the comma-delimited file ParserText.txt. The example writes the fields to Testfile.txt.

Using MyReader As New Microsoft.VisualBasic.FileIO.TextFieldParser("C:\ParserText.txt")
    MyReader.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited
    MyReader.Delimiters = New String() {","}
    Dim currentRow As String()
    While Not MyReader.EndOfData
        Try
            currentRow = MyReader.ReadFields()
            For Each currentField As String In currentRow
                My.Computer.FileSystem.WriteAllText(
                    "C://testfile.txt", currentField, True)
            Next
        Catch ex As Microsoft.VisualBasic.FileIO.MalformedLineException
            MsgBox("Line " & ex.Message & " is invalid.  Skipping")
        End Try
    End While
End Using

Remarks

In order to allow users to parse text files in multiple formats, the ReadFields method examines the values of TextFieldType, Delimiters, and FieldWidths, if they are specified, each time it is called. Users need to correctly configure the TextFieldType and FieldWidths or Delimiters properties, as appropriate. If TextFieldType is set to Delimited, and Delimiters is not set, or if TextFieldType is set to FixedWidth and FieldWidths, an exception is thrown.

If ReadFields encounters blank lines, they are skipped and the next non-blank line is returned.

If the ReadFields method cannot parse the current line, it raises an exception and does not move to the next line. This enables your application to attempt to parse the line again.

The following table lists examples of tasks involving the ReadFields method.

To	See
Read from a delimited file	How to: Read From Comma-Delimited Text Files
Read from a fixed-width file	How to: Read From Fixed-width Text Files

Applies to

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