11 Things About JavaScript Functions that .NET Developers Should Know: Part 1  

Tips for Becoming a JavaScript Developer 

Comprehensive and exhaustive JavaScript & Node.js testing best practices (August 2019)  

    public class Bill
    {
        public int Id { set; get; }
        public string Name { set; get; }

        public virtual ICollection<Transaction> Transactions { set; get; }
    }

    public class Transaction
    {
        public int Id { set; get; }
        public DateTime AddDate { set; get; }
        public int Amount { set; get; }

        [ForeignKey("BillId")]
        public virtual Bill Bill { set; get; }
        public int BillId { set; get; }
    }

    public class MyContext : DbContext
    {
        public DbSet<Bill> Bills { get; set; }
        public DbSet<Transaction> Transactions { get; set; }
    }

    public class Configuration : DbMigrationsConfiguration<MyContext>
    {
        public Configuration()
        {
            AutomaticMigrationsEnabled = true;
            AutomaticMigrationDataLossAllowed = true;
        }

        protected override void Seed(MyContext context)
        {
            var bill1 = new Bill { Name = "bill-1" };
            context.Bills.Add(bill1);

            for (int i = 0; i < 11; i++)
            {
                context.Transactions.Add(new Transaction
                {
                    AddDate = DateTime.Now.AddDays(-i),
                    Amount = 1000000000 + i,
                    Bill = bill1
                });
            }
            base.Seed(context);
        }
    }

    public static class Test
    {
        public static void RunTests()
        {
            Database.SetInitializer(new MigrateDatabaseToLatestVersion<MyContext, Configuration>());
            using (var context = new MyContext())
            {
                var sum = context.Transactions.Sum(x => x.Amount);
                Console.WriteLine(sum);
            }
        }
    }

SELECT 
         [GroupBy1].[A1] AS [C1]
         FROM ( SELECT 
                    SUM([Extent1].[Amount]) AS [A1]
                    FROM [dbo].[Transactions] AS [Extent1]
                    )  AS [GroupBy1]

 Arithmetic overflow error converting expression to data type int.

var sum2 = context.Transactions.Sum(x => (Int64)x.Amount);

SELECT 
      [GroupBy1].[A1] AS [C1]
         FROM ( SELECT 
                    SUM( CAST( [Extent1].[Amount] AS bigint)) AS [A1]
                    FROM [dbo].[Transactions] AS [Extent1]
               )  AS [GroupBy1]                  

var date = DateTime.Now.AddDays(10);
var sum3 = context.Transactions
                  .Where(x => x.AddDate > date)  
                  .Sum(x => (Int64)x.Amount);               

SELECT 
     [GroupBy1].[A1] AS [C1]
        FROM ( SELECT 
                    SUM( CAST( [Extent1].[Amount] AS bigint)) AS [A1]
                    FROM [dbo].[Transactions] AS [Extent1]
                    WHERE [Extent1].[AddDate] > @p__linq__0
              )  AS [GroupBy1]

The cast to value type 'Int64' failed because the materialized value is null.
Either the result type's generic parameter or the query must use a nullable type.

var date = DateTime.Now.AddDays(10);
var sum3 = context.Transactions
                  .Where(x => x.AddDate > date)
                  .Sum(x => (Int64?)x.Amount) ?? 0;

 var sum4 = context.Bills.First().Transactions.Sum(x => (Int64?)x.Amount) ?? 0;

SELECT 
     [Extent1].[Id] AS [Id], 
     [Extent1].[AddDate] AS [AddDate], 
     [Extent1].[Amount] AS [Amount], 
     [Extent1].[BillId] AS [BillId]
   FROM [dbo].[Transactions] AS [Extent1]
   WHERE [Extent1].[BillId] = @EntityKeyValue1

var entry = context.Bills.First();
var sum5 = context.Entry(entry).Collection(x => x.Transactions).Query().Sum(x => (Int64?)x.Amount) ?? 0;

SELECT 
    [GroupBy1].[A1] AS [C1]
     FROM ( SELECT 
               SUM( CAST( [Extent1].[Amount] AS bigint)) AS [A1]
                   FROM [dbo].[Transactions] AS [Extent1]
                    WHERE [Extent1].[BillId] = @EntityKeyValue1
            )  AS [GroupBy1]                  

how to manage HTML DOM
with vanilla JavaScript only?
for modern browsers and IE 11+ 

/**
     *
     * <p>
     *   check network is available or not <br/>
     *   internet connection is not matter,for check internet connection refer to IsInternetConnected() Method in this class
     * </p>
       * <p>
     *   Required Permission : <b>android.permission.ACCESS_NETWORK_STATE</b>
     * </p>
     * @param context
     * @return returns true if a network is available
     */
    public boolean isNetworkAvailable(Context context) {

        ConnectivityManager connectivityManager
                = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
        return activeNetworkInfo != null && activeNetworkInfo.isConnected();
    }

public class ProjectSettings
{
       public static NotificationsId=new NotificationsId();
       public static UrlAddresss=new UrlAddresss();
       public static SdPath=new SdPath();
       ......
}

ProjectSettings.NotificationsId.UpdateNotificationId

Toast.makeText(context, message, Toast.LENGTH_SHORT).show();

public interface IMessageUI
{
    void ShowToast(Context context,String message);
}

public class MessageUI impelement IMessageUI
{
      public void ShowToast(Context context,string message)
       {
              Toast.makeText(context, message, Toast.LENGTH_SHORT).show();
       }
}

      <receiver android:name=".AppStartReceiver" android:enabled="true">
            <intent-filter>
                <action android:name="org.telegram.start" />
                <action android:name="android.intent.action.BOOT_COMPLETED" />
            </intent-filter>
        </receiver>

public class AppStartReceiver extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent) {
        AndroidUtilities.runOnUIThread(new Runnable() {
            @Override
            public void run() {
                ApplicationLoader.startPushService();
            }
        });
    }
}

    <receiver android:name=".MusicPlayerReceiver" >
            <intent-filter>
                <action android:name="org.telegram.android.musicplayer.close" />
                <action android:name="org.telegram.android.musicplayer.pause" />
                <action android:name="org.telegram.android.musicplayer.next" />
                <action android:name="org.telegram.android.musicplayer.play" />
                <action android:name="org.telegram.android.musicplayer.previous" />
                <action android:name="android.intent.action.MEDIA_BUTTON" />
                <action android:name="android.media.AUDIO_BECOMING_NOISY" />
            </intent-filter>
        </receiver>

     From query= new Select()
               .from(Poem.class)
               .innerJoin(BankPoemsGroups.class)
               .on("poems.id=bank_poems_groups.poem")
               .where("BankGroup=?", String.valueOf(groupId));
        return query.execute();

@Table(name="poems")
public class Poem extends Model {

    public static String tableName="poems";
    public static  String codeColumn="code";
    public static  String titleColumn="title";
    public static  String bookColumn="book";
    ......

    @Column(name="code",index = true)
    public int Code;

    @Column(name="title")
    public String Title;

    @Column(name="book")
    public Book Book;
.....}

    From query= new Select()
               .from(Poem.class)
               .innerJoin(BankPoemsGroups.class)
               .on(Poem.TableName+"."+ Poem.IdColumn+"="+ BankPoemsGroups.TableName+"."+ BankPoemsGroups.PoemColumn)
               .where(Poem.BankGroupColumn+"=?", String.valueOf(groupId));
        return query.execute();

public class QueryConcater {
  public String GetInnerJoinQuery(String table1,String field1,String table2,String field2)
    {
        String query=table1 +"." +field1+"="+table2+"."+field2;
        return query;
    }
......
}

   return new Select()
                .from(Color.class)
                .innerJoin(ProductItem.class)
                .on(queryConcater.GetInnerJoinQuery(ProductItem.TableName,
                        ProductItem.ColorColumn, Color.TableName))
                .where(queryConcater.WhereConditionQuery
                        (ProductItem.TableName, ProductItem.ProductColumn), productId)
                .execute();

• وضعیت گوشی در حین باز شدن برنامه و در حین خطا چگونه بوده است.
• مشخصات گوشی
• این خطا به چه تعداد رخ داده است و برای چه تعداد کاربر
• گزارش گیری بر اساس اولین تاریخ رخداد خطا و آخرین تاریخ، نسخه سیستم عامل اندروید، ورژن برنامه شما و...

ACRA.getErrorReporter().handleException(caughtException);

 public  void CopyFile(String source,String destination,CopyFileListener copyFileListener) {
        try {
        InputStream in = new FileInputStream(source);
        OutputStream out = new FileOutputStream(destination);

        long fileLength=new File(source).length();
        // Transfer bytes from in to out
        byte[] buf = new byte[64*1024];
        int len;
        long total=0;
        while ((len = in.read(buf)) > 0) {
            out.write(buf, 0, len);
            total+=len;
            copyFileListener.PublishProgress(fileLength,total);
        }
        in.close();

            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public  void CopyFile(String source,String destination,CopyFileListener copyFileListener) throws IOException {

        InputStream in = new FileInputStream(source);
        OutputStream out = new FileOutputStream(destination);

        long fileLength=new File(source).length();
        // Transfer bytes from in to out
        byte[] buf = new byte[64*1024];
        int len;
        long total=0;
        while ((len = in.read(buf)) > 0) {
            out.write(buf, 0, len);
            total+=len;
            copyFileListener.PublishProgress(fileLength,total);
        }
        in.close();

            out.close();
    }

 public interface CopyFileListener
    {
        void PublishProgress(long fileSize,long copiedSize);
    }

 textView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                
            }
        });

public class MemoryWare {

    public interface CopyFileListener
    {
        void PublishProgress(long fileSize,long copiedSize);
    }
....
}

SetOnClickListener

 editText.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

            }

            @Override
            public void afterTextChanged(Editable s) {

            }
        });

  @Override
    public View getView(int position, View rowView, ViewGroup parent) {

        ViewHolder viewHolder=null;
        if(rowView==null)
        {
            // 1. Create inflater
            LayoutInflater inflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

            // 2. Get rowView from inflater
            rowView = inflater.inflate(R.layout.row_bank_group_list, parent, false);
            viewHolder=new ViewHolder();
            viewHolder.txtGroupName=(TextView) rowView.findViewById(R.id.text_groupName);
            rowView.setTag(viewHolder);
        }
        else
        {
            viewHolder=(ViewHolder)rowView.getTag();
        }
        viewHolder.txtGroupName.setText(getItem(position).getName());
        viewHolder.txtGroupName.setTypeface(new FontSystem().get_General_Font(context));
        viewHolder.txtGroupName.setTextColor(context.getResources().getColor(R.color.black));

        return rowView;
    }

File file=new File(sdcardPath,fileName);

if(file.CanWrite())
{
  .....
}

File file=new File(sdcardPath);

if(file.CanWrite())
{
file=new File(sdcardPath,filePath);
  .....
}

Environment.getExternalStorageDirectory()

/Data/Data

/Data/Data/Info.Dotnettips.MyApp

    /**
     * it will returns sd path for you
     *  <p>
     *  <b>Required Permission: </b>android.permission.READ_EXTERNAL_STORAGE<br/>
     * </p>
     * @return
     */
    public  List<String> GetExternalMounts() {
        final List<String> out = new ArrayList<>();
        String reg = "(?i).*vold.*(vfat|ntfs|exfat|fat32|ext3|ext4).*rw.*";
        String s = "";
        try {
            final Process process = new ProcessBuilder().command("mount")
                    .redirectErrorStream(true).start();
            process.waitFor();
            final InputStream is = process.getInputStream();
            final byte[] buffer = new byte[1024];
            while (is.read(buffer) != -1) {
                s = s + new String(buffer);
            }
            is.close();
        } catch (final Exception e) {
            e.printStackTrace();
        }

        // parse output
        final String[] lines = s.split("\n");
        for (String line : lines) {
            if (!line.toLowerCase(Locale.US).contains("asec")) {
                if (line.matches(reg)) {
                    String[] parts = line.split(" ");
                    for (String part : parts) {
                        if (part.startsWith("/"))
                            if (!part.toLowerCase(Locale.US).contains("vold"))
                                if(new File(part).canWrite())
                                    out.add(part);
                    }
                }
            }
        }
        return out;
    }

notesIntent.putExtra("PartyId", PartyId);
startActivity(notesIntent);

PartyId=getIntent().getLongExtra("PartyId",0);

i.putExtra(FilePickerActivity.EXTRA_ALLOW_MULTIPLE, false);
i.putExtra(FilePickerActivity.EXTRA_ALLOW_CREATE_DIR, false);
i.putExtra(FilePickerActivity.EXTRA_MODE, FilePickerActivity.MODE_FILE);

• برای ثابت‌ها از حروف بزرگ و _ استفاده کنید.
• برای متغیرهای خصوصی از حرف m در ابتدای نام متغیر استفاده کنید.
• برای متغیرهای استاتیک از حرف s در ابتدای نام متغیر استفاده کنید.

public class MyClass {
    public static final int SOME_CONSTANT = 42;
    public int publicField;
    private static MyClass sSingleton;
    int mPackagePrivate;
    private int mPrivate;
    protected int mProtected;
}

1. نام پکیج‌های ارائه شده توسط گوگل
2. نام پکیج‌های ثالث
3. نام پکیج‌های موجود در java و javax
4. پکیج‌های موجود در پکیج اصلی
   

public, protected, private,abstract, static, transient, volatile, synchronized, final, native.

Settings>Editor>Code Style>Arrangement

Settings>Editor>Completion>Case-sensitive Completion>None

A few words on Git. 

XAML – Tips and Tricks