MySql BulkCopy/Insert from DataReader

1. If item has bulk group id
2. If item is being inserted, not updated
3. Do a select into from a selection of items based on the bulk group id

    IF(@BulkGroupInsertId IS NULL OR EXISTS (SELECT * FROM DELETED))
    BEGIN
        -- Do Single Insert
    END
    ELSE
    BEGIN

    -- Bulk Insert

        INSERT INTO TeamSubscription (DivisionTeamId, PhoneNumber, DateCreated)
        SELECT tc.TeamId, p.MobilePhone, GETDATE()
        FROM
            -- Commented Out
        WHERE 
            -- Commented Out
        GROUP BY
            -- Commented Out

    END 

// this line is declaring a new variable named 'dt' 
// and assigning it an instance of a new DataTable
DataTable dt = new DataTable();
// this line is immediately overwriting the new DataTable 
// assigned to 'dt' with the DataTable returned from 'GetDataTableFromDGV'
dt = GetDataTableFromDGV(DGV);

DataTable dt = GetDataTableFromDGV(DBV);

foreach (DataGridViewColumn column in dgv.Columns)
{
    if (column.Visible)
    {
        dt.Columns.Add();
    }
} 

copy.ColumnMappings.Add(0, 1);
// etc...

// assumes the columns in the DataGridView are named as follows:
var columns = new[] {"Id", "Invoice_Id", "Software_Id", "Price", "Quantity", "Sum" }
var dt = new DataTable();
foreach (DataGridViewColumn column in dgv.Columns)
{
    // note: this is case-sensitive
    if (columns.Contains(column.Name))
    {
        dt.Columns.Add();
    }
}

copy.ColumnMappings.Add("Invoice_Id", "DestinationCol1");
copy.ColumnMappings.Add("Software_Id", "DestinationCol2");
// etc...

private DataTable GetDataTableFromDGV(DataGridView dgv)
{
    // use your actual columns names instead of Col1, Col2, etc...
    var columns = new[] {"Invoice_Id", "Software_Id", "Price", "Quantity", "Sum" }
    var dt = new DataTable();
    foreach (DataGridViewColumn column in dgv.Columns)
    {
        if (columns.Contains(column.Name))
        {
            dt.Columns.Add();
        }
    }

    foreach (DataGridViewRow row in dgv.Rows)
    {
        DataRow newRow = dt.NewRow();
        foreach (string columnName in columns)
        {
            newRow[columnName] = row.Cells[columnName].Value
        }

        dt.Rows.Add(newRow);
    }
    return dt;
}

private void InsertDTtoDB(string ConnectionString, string TableName, DataGridView DGV)
{
    DataTable dt = GetDataTableFromDGV(DGV);
    using (SqlConnection cn = new SqlConnection(ConnectionString))
    {
        cn.Open();
        using (SqlBulkCopy copy = new SqlBulkCopy(cn))
        {   
            // update the "DestinationCol[x]" values to the destination column names
            copy.ColumnMappings.Add("Invoice_Id", "DestinationCol1");
            copy.ColumnMappings.Add("Software_Id", "DestinationCol2");
            copy.ColumnMappings.Add("Price", "DestinationCol3");
            copy.ColumnMappings.Add("Quantity", "DestinationCol4");
            copy.ColumnMappings.Add("Sum", "DestinationCol5");
            copy.DestinationTableName = TableName;
            copy.WriteToServer(dt);
        }
    }
}

private DataTable GetDataTableFromDGV(DataGridView dgv)
{
    // assumes the columns in the DataGridView are named as follows:
    var columns = new[] {"Invoice_Id", "Software_Id", "Price", "Quantity", "Sum" }
    var dt = new DataTable();
    foreach (DataGridViewColumn column in dgv.Columns)
    {
        if (columns.Contains(column.Name))
        {
            dt.Columns.Add();
        }
    }

    foreach (DataGridViewRow row in dgv.Rows)
    {
        // check if the row has a null "Invoice_Id" and exclude
        if(row.Cells["Invoice_Id"] == null
        {
            continue;
        }

        DataRow newRow = dt.NewRow();
        foreach (string columnName in columns)
        {
            newRow[columnName] = row.Cells[columnName].Value
        }

        dt.Rows.Add(newRow);
    }
    return dt;
}