NEO Blockchain Quick Start Guide for .NET Developers

NEO Blockchain C# Developers Center of Excellence

The neo-csharpcoe project is an "umbrella" project for several initiatives related to providing tools and libraries (code), frameworks, how-to documentation, and best practices for enterprise application development using .NET/C#, C#.NEO and the NEO Blockchain software platform.

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Activity 9 - Deploy and test HelloWorld smart contract

Purpose

The purpose of this activity is to use deploy and test the HelloWorld smart contract created in the previous activity. It uses the the neo-gui-developer tool that was build in an earlier activity. This activity also uses the NEO Docker container that was installed and configured also in an earlier activity.

Goals, Non-Goals and Assumptions

Ensure you have a working and properly configured set of NEO developer tools for creating and building smart contracts in Visual Studio with the C# programming language

Principles

Provide reliable documentation: timely, accurate, visual, and complete
Save as much of a person's time as possible
Use open source software whenever possible

Drivers

Need in the NEO .NET developer community to have concise and easy-to-follow documentation to enable people to get up to speed developing NEO smart contracts in as short a time as possible

Start (reset) the NEO privatenet Docker container

Start the NEO privatenet Docker container by opening PowerShell and running the following commands:

docker container list
docker stop neo-privnet-with-gas
docker container list
docker rm neo-privnet-with-gas
docker container list
docker run -d --name neo-privnet-with-gas -p 20333-20336:20333-20336/tcp -p 30333-30336:30333-30336/tcp metachris/neo-privnet-with-gas
docker container list
pause

Script: NEO Docker Reset (./scripts/neodockerreset.bat.txt)

The script produces the following output:

Figure 9.1. NEO Docker Reset

Test the NEO privatenet Docker Container

To test the NEO Docker container, run following script:
```
REM cd opt/neo-python
REM python3 prompt.py -p
REM block 0
docker exec -it neo-privnet-with-gas /bin/bash
pause
```
Script: NEO Docker Python CLI/Shell (./scripts/neodockerpshell.bat.txt)

When the bash shell starts, enter the following commands:
```
cd opt/neo-python
python3 prompt.py -p
block 0
```

Configure `neo-gui (developer)` to use the NEO privatenet Docker container

Open Windows Explorer and navigate to C:\NEO\neo-gui-developer\neo-gui\bin and right-click on the the Debug folder and delete it (and all of of the folder's contents).

$C:\NEO\neo-gui-developer\neo-gui\bin$

Figure 9.2. C:\NEO\neo-gui-developer\neo-gui\bin
Navigate to C:\NEO\neo-gui-developer.

$C:\NEO\neo-gui-developer$

Figure 9.3. C:\NEO\neo-gui-developer
Double-click neo-gui.sln to open the neo-gui-developer project in Visual Studio.

Figure 9.4. Visual Studio: neo-gui project
In Visual Studio, replace the contents of config.json with the contents of config.neodocker.json.

Figure 9.5. Visual Studio: config.json

NOTE: If config.neodocker.json is not part of your project, you can download it from here (./json/config.neodocker.json) and place it in the C:\NEO\neo-gui-developer\neo-gui folder. Right-click on the neo-gui project folder in Visual Studio and select Add > Existing Item... > *.*. Select config.neodocker.json and click Add.
Similarly, replace the contents of protocol.json with the contents of protocol.neodocker.json.

Figure 9.6. Visual Studio: protocol.json

NOTE: If protocol.neodocker.json is not part of your project, you can download it from here (./json/protocol.neodocker.json) and place it in the C:\NEO\neo-gui-developer\neo-gui folder. Right-click on the neo-gui project folder in Visual Studio and select Add > Existing Item... > *.*. Select protocol.neodocker.json and click Add.
In Visual Studio, click Start to rebuild and start neo-gui. It should starting syncing with the NEO privatenet Docker container.

Figure 9.7. neo-gui: Running against the NEO privatenet Docker container

NOTE: If you made the optional code change in Activity 5 - Build and test NEO developer tool projects (from source), you will see the name of your NEO blockchain folder in the title bar (e.g. DockerChainTestNet).

Create a new development wallet

From the neo-gui menu bar, click Wallet > New Wallet Database....

Figure 9.8. neo-gui: Wallet > New Wallet Database...
The following New Wallet dialog but will appear. Click browse.

Figure 9.9. neo-gui: New Wallet dialog
Select a folder where you want your wallet to be created, enter the file name for the wallet database, and click Save.

Figure 9.10. neo-gui: Wallet Location

NOTE: Think of these as temporary development wallets that you will need to recreate every time you reset the NEO privatenet Docker container. There's no need to back them up.

NOTE: A good suggestion is to include the name of the blockchain database folder that appears in neo-gui title bar (assuming you made this source code change in Activity 5) in the name of your wallet file.

NOTE: The neo-gui-developer project only creates wallet databases using .db3 format files (SQLLite database files). Other versions of neo-gui use JSON files. Note the difference.
Enter a password to protect your wallet. Confirm your password by re-entering into the second field.

Figure 9.11. neo-gui: Wallet Password
The creation of your wallet is complete. One default account address has been created.

NOTE: This address will be different every time you create a new wallet.

Figure 9.12. neo-gui: Wallet Created

Import the existing Developer account from the NEO privatenet Docker container

To get some NEO/Gas, there is a preconfigured Developer account configured into the NEO private Docker container. To import this account, right-click on the newly created account and select Import > Import from WIF....

Figure 9.13. neo-gui: Import > Import from WIF...
The following Import Private Key dialog box will be displayed. Enter the WIF key provided in the NEO Docker container documentation [NEODOCKER1] and click OK.
```
WIF key: KxDgvEKzgSBPPfuVfw67oPQBSjidEiqTHURKSDL1R7yGaGYAeYnr
```
Figure 9.14. neo-gui: Import Private Key
The result should be that you've created the following second account at address:
```
Address: AK2nJJpJr6o664CWJKi1QRXjqeic2zRp8y
```
NOTE: You may need to select Wallet > Rebuild Index for the non-zero NEO/Gas to appear next to the new account address.

Figure 9.15. neo-gui: Second Address with NEO/Gas

Deploy your smart contract (HelloWorld 1.0)

Open Visual Studio 2017 to create a new NEO smart contract project.

Figure 9.16. Visual Studio 2017
Select File > New > Project... to open the New Project dialog box. Select Visual C#. Select NeoContract. Click OK to close this dialog box and create a new NeoContract solution and project in Visual Studio.

Figure 9.17. Visual Studio: Create a New NeoContract Project

NOTE: If you have created previous NeoContract projects, your project may be called NeoContract2, NeoContract3, or whatever you chose to name the project. Remember the project name and path because you will need to find the AVM file later on in this activity.
Visual Studio may take a few minutes to create the NeoContract project.

Figure 9.18. Visual Studio: Creating the NeoContract Project
Right-click on the NeoContract project folder and select Build. Note the highlighted messages in the Build section of the Output panel. These 2 message indicate the Visual Studio was able to create both the NEO virtual machine byte code file as well as the Application Binary Interace (ABI) file (in JSON format).

NOTE: If you don't see these 2 messages, the most likely senarios are:
- neon.dll wasn't published properly. Go back to Task 6 of this activity.
- The Path environment variable was not set correctly. Go back to Task 16 of this activity.
- You had opened Visual Studio before you set the Path environment variable. Close Visual Studio and then go back to Task 20.
Figure 9.19. Visual Studio: Building the NeoContract Project

Deploy your first smart contract

From the neo-guimenu bar, select Advanced > Deploy Contract... to display the Deploy Contact dialog box.

Figure 9.20. neo-gui: Deploy Contract Dialog Box
Enter the following information in the Deploy Contract dialog box.

In the Information section, enter something appropriate for each field. These fields must be non-blank.
In the Return Type section, leave these fields empty (for this particular smart contract).
Click the Need Storage check box so that a check is displayed.
Click Load to the AVM file created by your Visual Studio project (e.g. C:\NEO\repos\NeoContract1\NeoContract1\bin\Debug\NeoContract1.avm). .

When the above information is complete, click Deploy on the Deploy Contract dialog box to complete the preparation steps for neo-gui to deploy the VM byte code for your contract.

The Script Hash will be displayed in the Script Hash dialog box. Click copy to have the script hash on the clipboard.

Figure 9.21. neo-gui: Script Hash

NOTE: The script hash is a hash of the VM byte code read in from your AVM (.avm) byte code file. This is the same script hash value that appears at the bottom of the Deploy Contract dialog box after you had loaded your AVM file.

NOTE: If you forget to click copy to save a copy of the script hash to the clipboard, you can always retrieve the script hash value by reselecting Advanced > Deploy Contract... to display the Deploy Contact dialog box and reloading your AVM file. The script hash will appear near the bottom of the Deploy Contract dialog box. If all you need is the script hash, you don't need to complete the fields in the Information or Return Type sections. Click Cancel this time instead of Deploy.

NOTE: If you haven't changed the code for your smart contract (and hence, the AVM file created by Visual Studio/neon will be the same), it will have the same script hash value. neo-gui doesn't create a new script hash value every time you deploy a smart contract. It only calculates a new hash value if the code for the smart contract has changed.
Immediately after you copy the script hash in the previous task, click close on the Script Hash dialog box to display the following Invoke Contract dailog.

Click Test and then click Invoke. It is with these 2 actions that your smart contract will be deployed to the NEO privatenet.

Figure 9.22. neo-gui: Invoke Contract Dialog Box
When the Transaction successful dialog box appears, click close. There is no need to copy of the transaction hash (TXID).

Figure 9.23. neo-gui: Transaction Successful Dialog Box
In neo-gui, click on the Transaction History tab to see the list of transactions that have been executed on the NEO privaenet.

NOTE: The first transaction is pending "unconfirmed" status; it has not been confirmed by the nodes on the blockchain.

Figure 9.24. neo-gui: Transaction History

You need to wait until the "unconfirmed" state changes to a number (e.g. 1). In this case, some time has elapsed and 3 blocks have confirmed your most recent transaction.

NOTE: Then you can click on the Event Log tab to see if your smart contract has called Runtime.Notify() or Runtime.Log() to post messages to the NEO Event Log.

Figure 9.24. neo-gui: Transaction History

Invoke your first smart contract

From the neo-guimenu bar, select Advanced > Invoke Contract... to display the Invoke Contact dialog box.

Paste the script hash from the deployment tasks into the ScriptHash field. If you deployment was successful, the rest of the fields on the form should be filled with the values you entered on the Deploy Contract dialog box.

NOTE: If the fields are blank, go back to Task 21 and start over. Pay particular attention to the instructions in Task 23.

Figure 9.25. neo-gui: Invoke Contract Dialog Box
Click Test to invoke your contract.

Figure 9.26. neo-gui: Invoke Contract Dialog Box: Test
The results (return values) will appear in the text box at the bottom of the dialog.

NOTE: You may have to click it twice.

Figure 9.27. neo-gui: Invoke Contract Dialog Box: Results
Returning to the neo-gui Account tab, you will notice the your NEO/Gas has been reduced.

NOTE: 490 Gas is used to deploy a contract. 1 Gas is used to invoke a transaction.

Figure 9.28. neo-gui Account Tab

Create your second smart contract (HelloWorld 2.0)

Follow the pattern set out in the previous tasks to create a new NeonContract project (e.g. NeoContract2).

NOTE: If you have created previous NeoContract projects, your project may be called NeoContract3, NeoContract4, or whatever you chose to name the project. Remember the project name and path because you will need to find the AVM file later on in this activity.

Make a few changes to the default smart contract:

Change Main() to a accept a single integer parameter called value.
Add a return value * 100; statement to the end of Main().

Figure 9.29. HelloWorld 2.0 Smart Contract

Your code should not look similar to the following:

using System;
using System.Numerics;
using Neo.SmartContract.Framework;
using Neo.SmartContract.Framework.Services.Neo;

namespace NeoContract2
{
    public class HelloWorld : SmartContract
    {
        public static int Main(int value)
        {
            Storage.Put(Storage.CurrentContext, "Hello", "World!");

            return value * 100;
        }
    }
}

Code 9.1: HelloWorld 2.0

Deploy your second smart contract

Follow the pattern set out in the previous tasks to deploy your HelloWorld 2.0 smart contract. Fill in the fields on the Deploy Contract dialog box.

NOTE: On the Deploy Contract dialog box, in the Return Type section, you need to provide a string of 2-digit codes denoting the data type of:

Inbound parameters
Return value

The data type codes for the parameters and return value can be found in the following table.

Parameter/Return Type	Description
Signature	00
Boolean	01
Integer	02
Hash160 (160-bit hash value)	03
Hash256 (256-bit hash value)	04
ByteArray, Object	05
PublicKey	06
String	07
Array	10
InteropInterface	f0
Void	ff
Table 9.1: NEO Smart Contract Parameter/Return Types [NEOPARMTYPES]

For HelloWorld 2.0, you need to specify 02 and 02 for the single integer inbound parameter and the integer return value.

Figure 9.30. HelloWorld 2.0: Deploy Contract

Load the AVM file for HelloWorld 2.0 and click Deploy on the Deploy Contract dialog box.

Figure 9.31. HelloWorld 2.0: Load Contract
Copy the script hash value and click close on the Script Hash dialog box.

Figure 9.32. HelloWorld 2.0: Script Hash
To complete the deployment, click Test and then Invoke on the Invoke Contract dialog box.

Figure 9.33. HelloWorld 2.0: Complete Deployment
Deployment complete. Click close.

Figure 9.34. HelloWorld 2.0: Deployment Complete

Invoke your second smart contract

On the right-side of the Invoke Contract dialog box, in the Contract Parameters section, click on Integer=(null) to dislay the Parameter Editor dialog box. Enter 123 and click Add.

Figure 9.35. HelloWorld 2.0: Parameters
Click Test to call your smart contract. The results (return value) will appear in the text box at the bottom of the dialog box.

Figure 9.36. HelloWorld 2.0: Test
To see the list of contracts you have deployed,dFrom the neo-guimenu bar, select Advanced > List Contracts to display the Smart Contract Monitor dialog box.

Figure 9.37. neo-gui: Smart Contract Monitor

The tasks for this activity are complete. Proceed to Activity 10 - Celebrate.

Script Library

NEO Docker Download/Install/Run (./scripts/neodockerinstall.bat.txt)
NEO Docker Stop/Remove (./scripts/neodockeruninstall.bat.txt)
NEO Docker Start (./scripts/neodockerstart.bat.txt)
NEO Docker Stop (./scripts/neodockerstop.bat.txt)
NEO Docker Restart (./scripts/neodockerrestart.bat.txt)
NEO Docker Reset (./scripts/neodockerreset.bat.txt)
NEO Docker Python CLI/Shell (./scripts/neodockerpshell.bat.txt)

References

[QUICKSTART] neo-csharpcoe, NEO Blockchain Quick Start Guide for .NET Developers from https://github.com/mwherman2000/neo-dotnetquickstart/blob/master/README.md
[NEODOCKER1] metachris, metachris/neo-privnet-with-gas from [https://hub.docker.com/r/metachris/neo-privnet-with-gas/]https://hub.docker.com/r/metachris/neo-privnet-with-gas/()
[NEOPARMTYPES] Neo Project, Smart Contract Parameters and Return Values from http://docs.neo.org/en-us/sc/tutorial/Parameter.html

Other Good Resources

[NEOPYTHONTUTORIAL] Nick Fujita, NEO Smart Contracts Tutorial: helloWorld (Python) from https://steemit.com/neo/@z0yo/neo-smart-contracts-tutorial-helloworld
[NEOPYTHONTUTORIALVIDEO] Nick Fujita, NEO Smart Contract Tutorial - Hello World (Python) from https://www.youtube.com/watch?v=9Ha_5RdOQrA
[NEOGUIDEVPULL38] Michael Herman. Pull Request #38 to have the config.neodocker.json and protocol.neodocker.json files added to the neo-gui-developer project from CityOfZion/neo-gui-developer#38

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09-deploytestsmartcontract.md

09-deploytestsmartcontract.md

NEO Blockchain Quick Start Guide for .NET Developers

Activity 9 - Deploy and test HelloWorld smart contract

Purpose

Goals, Non-Goals and Assumptions

Principles

Drivers

Start (reset) the NEO privatenet Docker container

Test the NEO privatenet Docker Container

Configure `neo-gui (developer)` to use the NEO privatenet Docker container

Create a new development wallet

Import the existing Developer account from the NEO privatenet Docker container

Deploy your smart contract (HelloWorld 1.0)

Deploy your first smart contract

Invoke your first smart contract

Create your second smart contract (HelloWorld 2.0)

Deploy your second smart contract

Invoke your second smart contract

Script Library

References

Other Good Resources

Files

09-deploytestsmartcontract.md

Latest commit

History

09-deploytestsmartcontract.md

File metadata and controls

NEO Blockchain Quick Start Guide for .NET Developers

Activity 9 - Deploy and test HelloWorld smart contract

Purpose

Goals, Non-Goals and Assumptions

Principles

Drivers

Start (reset) the NEO privatenet Docker container

Test the NEO privatenet Docker Container

Configure neo-gui (developer) to use the NEO privatenet Docker container

Create a new development wallet

Import the existing Developer account from the NEO privatenet Docker container

Deploy your smart contract (HelloWorld 1.0)

Deploy your first smart contract

Invoke your first smart contract

Create your second smart contract (HelloWorld 2.0)

Deploy your second smart contract

Invoke your second smart contract

Script Library

References

Other Good Resources

Configure `neo-gui (developer)` to use the NEO privatenet Docker container