Q for advanced programmer re DLLs

[kenz987]

Would one of you advanced programmers show me an example of how to call a DLL (preferably User32 or Kernel) from a NT indicator? Thanks, Ken.

[kenz987]

MsgBox works

The following code works as is - seems if I place a Reference to user32 it stops working.
//================================================== ==
#region Using declarations
using System;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.ComponentModel;
using System.Xml.Serialization;
using NinjaTrader.Cbi;
using NinjaTrader.Data;
using NinjaTrader.Gui.Chart;
using System.Runtime.InteropServices;
using System.Text;
#endregion
//
//
// This namespace holds all indicators and is required. Do not change it.
namespace NinjaTrader.Indicator
{
public class call_msg
{
[DllImport("User32.dll", EntryPoint="MessageBox", CharSet=CharSet.Auto)]
public static extern int MsgBox(int hWnd, String text, String caption, uint type);
}
/// <summary>
/// zTestMsgBox
/// </summary>
[Description("zTestMsgBox")]
public class zTestMsgBox : Indicator
{
#region Variables
// User defined variables (add any user defined variables below)
string sData = "Hello World";
#endregion


/// <summary>
/// This method is used to configure the indicator and is called once before any bar data is loaded.
/// </summary>
protected override void Initialize()
{
Add(new Plot(Color.FromKnownColor(KnownColor.Yellow), PlotStyle.Line, "Plot0"));
CalculateOnBarClose = true;
Overlay = false;
PriceTypeSupported = false;
PaintPriceMarkers = false;
}

/// <summary>
/// Called on each bar update event (incoming tick)
/// </summary>
protected override void OnBarUpdate()
{
if(CurrentBar > 0) return;
call_msg.MsgBox(0, sData, "PInvoke Sample", 0);
}

#region Properties
...
.#endregion

[NinjaTrader_JoshP]

Thanks for posting your code and findings Ken. I am sure someone will benefit from it.

I think I mentioned this before in another thread, but if not here it is again. Since this is not a supported item, we will not be able to assist in this endeavor. Good luck though.

[kenz987]

Error

Error - Trying to read or write protected memory.
Got same message on other calls.
Well, yes, I am trying to read memory - I want to get certain data from inside the kernel, but it should be allowed.
ANYONE have a solution for this... PLEASE???
//==============================================
#region Using declarations
using System;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.ComponentModel;
using System.Xml.Serialization;
using NinjaTrader.Cbi;
using NinjaTrader.Data;
using NinjaTrader.Gui.Chart;
using System.Runtime.InteropServices;
using System.Text;
#endregion
//
//
// This namespace holds all indicators and is required. Do not change it.
namespace NinjaTrader.Indicator
{
public class call_k32
{
[DllImport("kernel32.dll", EntryPoint="GetComputerNameA")]
public static extern long GetCompName(StringBuilder buf, long lLgth);
// this compiled, gives error trying to read protected memory
}

/// <summary>
/// zTestGetCompName
/// </summary>
[Description("zTestGetCompName")]
public class zTestGetCompName : Indicator
{
#region Variables
// User defined variables (add any user defined variables below)
long lRtn = 0;
long lBufLgth = 0;
#endregion


/// <summary>
/// This method is used to configure the indicator and is called once before any bar data is loaded.
/// </summary>
protected override void Initialize()
{
Add(new Plot(Color.FromKnownColor(KnownColor.Yellow), PlotStyle.Line, "Plot0"));
CalculateOnBarClose = true;
Overlay = false;
PriceTypeSupported = false;
PaintPriceMarkers = false;
}

/// <summary>
/// Called on each bar update event (incoming tick)
/// </summary>
protected override void OnBarUpdate()
{
if(CurrentBar > 0) return;
StringBuilder sb = new StringBuilder(256);
lBufLgth = sb.Capacity;
lRtn = call_k32.GetCompName(sb, lBufLgth);
}

... etc

[kenz987]

Josh

This is no different in concept than StreamWriter and other items that you folks have provided examples for.

[NinjaTrader_JoshP]

Ken,

It is outside the scope of what we offer support for. This is C# and it is impossible for us to support all aspects of C# here. Thank you for understanding.

[mefTrader]

Have a look at http://msdn.microsoft.com/en-us/libr...8VS.71%29.aspx

[hana_maui]

Hi, I have a similar question regarding DLLs and indicators but in the inverse way.

Is there any way to call Ninja Indicators from DLL functions provided through the ATI ?

Your advise is highly appreciated.

Thank you.

[NinjaTrader_Austin]

hana_maui, it is not possible to call indicators from the ATI .dll.