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check if Ai Channel exists in task?

I want to write a simple If Then Else statement in order to do something if a specific Ai channel exists in the task.  What is an easy way to do this? 

 

I need to be able to find out what specific channels are in the task so that I can map its plotted data to the correct WaveformGraph on my form.  And if the channel does not exist, do nothing (don't try to plot data to its waveform graph).   

 

 

 

 myTask = New DAQmx.Task

'check what checkboxes are checked and then create each Ai Channel accordingly
            Try
                'Create Daq virtual channels
                If ch0RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai0", lblCh0Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch1RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai1", lblCh1Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch2RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai2", lblCh2Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch3RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai3", lblCh3Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch4RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai4", lblCh4Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch5RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai5", lblCh5Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch6RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai6", lblCh6Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch7RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai7", lblCh7Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch8RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai16", lblCh8Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch9RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai17", lblCh9Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch10RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai18", lblCh10Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch11RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai19", lblCh11Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch12RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai20", lblCh12Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch13RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai21", lblCh13Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch14RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai22", lblCh14Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                If ch15RecordData = True Then
                    myTask.AIChannels.CreateVoltageChannel("cDAQ9184-1A4BA5FMod1/ai23", lblCh15Wfg.Text, AITerminalConfiguration.Differential, -10, 10, "Linear Scale")
                End If
                myTask.Stop()

            Catch ex As DaqException
                MessageBox.Show(ex.Message)
            End Try

 Try
                    data = reader.ReadWaveform(readRate)




'Stream each channel's data to its specific Wafeformgraph.  This code obviously will not work if the channel does not exist in the task.  

                    wfgCh0.PlotWaveformAppend(data(0)) : numEdtCh0.Value = data(0).Samples(readRate - 1).Value
                    wfgCh1.PlotWaveformAppend(data(1)) : numEdtCh1.Value = data(1).Samples(readRate - 1).Value
                    wfgCh2.PlotWaveformAppend(data(2)) : numEdtCh2.Value = data(2).Samples(readRate - 1).Value
                    wfgCh3.PlotWaveformAppend(data(3)) : numEdtCh3.Value = data(3).Samples(readRate - 1).Value
                    wfgCh4.PlotWaveformAppend(data(4)) : numEdtCh4.Value = data(4).Samples(readRate - 1).Value
                    wfgCh5.PlotWaveformAppend(data(5)) : numEdtCh5.Value = data(5).Samples(readRate - 1).Value
                    wfgCh6.PlotWaveformAppend(data(6)) : numEdtCh6.Value = data(6).Samples(readRate - 1).Value
                    wfgCh7.PlotWaveformAppend(data(7)) : numEdtCh7.Value = data(7).Samples(readRate - 1).Value
                    wfgCh8.PlotWaveformAppend(data(8)) : numEdtCh8.Value = data(8).Samples(readRate - 1).Value
                    wfgCh9.PlotWaveformAppend(data(9)) : numEdtCh9.Value = data(9).Samples(readRate - 1).Value
                    wfgCh10.PlotWaveformAppend(data(10)) : numEdtCh10.Value = data(10).Samples(readRate - 1).Value
                    wfgCh11.PlotWaveformAppend(data(11)) : numEdtCh11.Value = data(11).Samples(readRate - 1).Value
                    wfgCh12.PlotWaveformAppend(data(12)) : numEdtCh12.Value = data(12).Samples(readRate - 1).Value
                    wfgCh13.PlotWaveformAppend(data(13)) : numEdtCh13.Value = data(13).Samples(readRate - 1).Value
                    wfgCh14.PlotWaveformAppend(data(14)) : numEdtCh14.Value = data(14).Samples(readRate - 1).Value
                    wfgCh15.PlotWaveformAppend(data(15)) : numEdtCh15.Value = data(15).Samples(readRate - 1).Value
                Catch ex As DaqException
                    MessageBox.Show(ex.Message)
                    reader = Nothing
                    data = Nothing
                    swScopeOnOff.Value = False
                    Return
                End Try

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Message 1 of 3
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Hi,

 

Were you able to make any progress on this?

 

One option might be to use channel expansion to create the virtual channels, and then use a for loop to go through an array of the channels rather than hardcoding all the variables individually.

 

Regards,

 

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Message 2 of 3
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Yes, I found that out.  Thank you.  All is good now.

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