ProcessStartInfo.RedirectStandardInput Property
Definition
Important
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Gets or sets a value indicating whether the input for an application is read from the StandardInput stream.
public:
property bool RedirectStandardInput { bool get(); void set(bool value); };public bool RedirectStandardInput { get; set; }member this.RedirectStandardInput : bool with get, setPublic Property RedirectStandardInput As BooleanProperty Value
true if input should be read from StandardInput; otherwise, false. The default is false.
Examples
The following example illustrates how to redirect the StandardInput stream of a process. The sort command is a console application that reads and sorts text input.
The example starts the sort command with redirected input. It then prompts the user for text, and passes the text to the sort process through the redirected StandardInput stream. The sort results are displayed to the user on the console.
#using <System.dll>
using namespace System;
using namespace System::IO;
using namespace System::Diagnostics;
using namespace System::ComponentModel;
int main()
{
Console::WriteLine( "Ready to sort one or more text lines..." );
// Start the Sort.exe process with redirected input.
// Use the sort command to sort the input text.
Process^ myProcess = gcnew Process;
if ( myProcess )
{
myProcess->StartInfo->FileName = "Sort.exe";
myProcess->StartInfo->UseShellExecute = false;
myProcess->StartInfo->RedirectStandardInput = true;
myProcess->Start();
StreamWriter^ myStreamWriter = myProcess->StandardInput;
if ( myStreamWriter )
{
// Prompt the user for input text lines to sort.
// Write each line to the StandardInput stream of
// the sort command.
String^ inputText;
int numLines = 0;
do
{
Console::WriteLine( "Enter a line of text (or press the Enter key to stop):" );
inputText = Console::ReadLine();
if ( inputText && inputText->Length > 0 )
{
numLines++;
myStreamWriter->WriteLine( inputText );
}
}
while ( inputText && inputText->Length != 0 );
// Write a report header to the console.
if ( numLines > 0 )
{
Console::WriteLine( " {0} sorted text line(s) ", numLines.ToString() );
Console::WriteLine( "------------------------" );
}
else
{
Console::WriteLine( " No input was sorted" );
}
// End the input stream to the sort command.
// When the stream closes, the sort command
// writes the sorted text lines to the
// console.
myStreamWriter->Close();
}
// Wait for the sort process to write the sorted text lines.
myProcess->WaitForExit();
myProcess->Close();
}
}
using System;
using System.IO;
using System.Diagnostics;
using System.ComponentModel;
namespace ProcessStandardInputSample
{
class StandardInputTest
{
static void Main()
{
Console.WriteLine("Ready to sort one or more text lines...");
// Start the Sort.exe process with redirected input.
// Use the sort command to sort the input text.
using (Process myProcess = new Process())
{
myProcess.StartInfo.FileName = "Sort.exe";
myProcess.StartInfo.UseShellExecute = false;
myProcess.StartInfo.RedirectStandardInput = true;
myProcess.Start();
StreamWriter myStreamWriter = myProcess.StandardInput;
// Prompt the user for input text lines to sort.
// Write each line to the StandardInput stream of
// the sort command.
String inputText;
int numLines = 0;
do
{
Console.WriteLine("Enter a line of text (or press the Enter key to stop):");
inputText = Console.ReadLine();
if (inputText.Length > 0)
{
numLines++;
myStreamWriter.WriteLine(inputText);
}
} while (inputText.Length > 0);
// Write a report header to the console.
if (numLines > 0)
{
Console.WriteLine($" {numLines} sorted text line(s) ");
Console.WriteLine("------------------------");
}
else
{
Console.WriteLine(" No input was sorted");
}
// End the input stream to the sort command.
// When the stream closes, the sort command
// writes the sorted text lines to the
// console.
myStreamWriter.Close();
// Wait for the sort process to write the sorted text lines.
myProcess.WaitForExit();
}
}
}
}
Imports System.IO
Imports System.Diagnostics
Imports System.ComponentModel
Namespace Process_StandardInput_Sample
Class StandardInputTest
Shared Sub Main()
Console.WriteLine("Ready to sort one or more text lines...")
' Start the Sort.exe process with redirected input.
' Use the sort command to sort the input text.
Using myProcess As New Process()
myProcess.StartInfo.FileName = "Sort.exe"
myProcess.StartInfo.UseShellExecute = False
myProcess.StartInfo.RedirectStandardInput = True
myProcess.Start()
Dim myStreamWriter As StreamWriter = myProcess.StandardInput
' Prompt the user for input text lines to sort.
' Write each line to the StandardInput stream of
' the sort command.
Dim inputText As String
Dim numLines As Integer = 0
Do
Console.WriteLine("Enter a line of text (or press the Enter key to stop):")
inputText = Console.ReadLine()
If inputText.Length > 0 Then
numLines += 1
myStreamWriter.WriteLine(inputText)
End If
Loop While inputText.Length <> 0
' Write a report header to the console.
If numLines > 0 Then
Console.WriteLine($" {numLines} sorted text line(s) ")
Console.WriteLine("------------------------")
Else
Console.WriteLine(" No input was sorted")
End If
' End the input stream to the sort command.
' When the stream closes, the sort command
' writes the sorted text lines to the
' console.
myStreamWriter.Close()
' Wait for the sort process to write the sorted text lines.
myProcess.WaitForExit()
End Using
End Sub
End Class 'StandardInputTest
End Namespace 'Process_StandardInput_Sample
Remarks
A Process can read input text from its standard input stream, typically the keyboard. By redirecting the StandardInput stream, you can programmatically specify the input of a process. For example, instead of using keyboard input, you can provide text from the contents of a designated file or output from another application.
Note
You must set UseShellExecute to false if you want to set RedirectStandardInput to true. Otherwise, writing to the StandardInput stream throws an exception.
