delegate void CheckStringDelegate(int i);

void CheckString(int i)
{
    //Do smth with i row from DataGridView
}

private: System::Void ChBut_Click(System::Object^  sender, System::EventArgs^  e) 
{
	//CheckOperation();
	for (int i=0; i<(dataGridView1->RowCount);i++) 
	{
		//IAsyncResult ^ caller = ChBut->BeginInvoke(gcnew CheckStringDelegate(this, &Form1::CheckString), i);
		CheckStringDelegate ^ action = gcnew CheckStringDelegate(this, &Form1::CheckString);
		this->BeginInvoke (action, i);
	}
}

void CheckString(int i)
{
	System::Diagnostics::Trace::WriteLine("Start processung");
	System::Diagnostics::Trace::WriteLine("End processung");
}

	delegate void CheckStringDelegate(int i);

	void CheckString(int i)
	{
		//do smth with i-row of the DataGridView
	}

	void UpdateDeviceTable()
	{
		array <IAsyncResult^> ^ res = gcnew array <IAsyncResult^> (DevicesTable->RowCount) ;
		CheckStringDelegate ^ action;
			
		for (int i=0;i<DevicesTable->RowCount;i++)
		{
			action = gcnew CheckStringDelegate(this, &Form1::CheckString);
			res [i]= action->BeginInvoke (i, nullptr, nullptr );
		}
					
		for(int i=0;i<DevicesTable->RowCount;i++)
		{
			res[i]->AsyncWaitHandle->WaitOne();
		}
			
		auto MyWriter = gcnew IO::StreamWriter(TempDescrTextBox->Text, true, System::Text::Encoding::GetEncoding(1251));
	}