hoTools.Query.SqlFile.Load C# (CSharp) Method

        public string Load()
        {
            try
            {
                string s = File.ReadAllText(_fullName).Trim();
                _readTime = DateTime.Now; // avoid 
                IsChanged = false;
                return s;
            }
            catch (Exception e)
            {
                MessageBox.Show($"File '{_fullName}'\r\n{e}", @"Error reading file!");
                return "";
            }
        }
    }

        /// <summary>
        /// Load sql string from *.sql File into active TabPage with TextBox inside. 
        /// <para/>- Update and save the list of sql files 
        /// </summary>
        public void LoadTabPagePerFileDialog()
        {
            TabPage tabPage;
            // no tab page exists
            if (_tabControl.TabPages.Count == 0)
            {
                tabPage = AddTab();
            }
            else
            {
                // get TabPage
                if (_tabControl.SelectedIndex < 0) return;
                tabPage = _tabControl.TabPages[_tabControl.SelectedIndex];

                // If contend changed: Store first
                SqlFile sqlFile = (SqlFile)tabPage.Tag;
                if (sqlFile.IsChanged)
                {
                    DialogResult result = MessageBox.Show($"Old File: '{sqlFile.FullName}'",
                        @"First store old File? ", MessageBoxButtons.YesNoCancel);
                    if (result == DialogResult.Cancel) return;
                    if (result == DialogResult.Yes)
                    {
                        Save(tabPage);
                        sqlFile.IsChanged = false;
                        tabPage.ToolTipText = ((SqlFile)tabPage.Tag).FullName;
                    }
                }


            }
            OpenFileDialog openFileDialog = new OpenFileDialog
            {
                InitialDirectory = @"c:\temp\sql",
                RestoreDirectory = true,
                Filter = @"sql files (*.sql)|*.sql|All files (*.*)|*.*",
                FilterIndex = 1
            };


            if (openFileDialog.ShowDialog() == DialogResult.OK)

            {
                string fileName = openFileDialog.FileName;
                if (!string.IsNullOrEmpty(fileName))
                {
                    // get TextBox
                    var textBox = (TextBoxUndo)tabPage.Controls[0];
                    SqlFile sqlFile = new SqlFile(this, fileName, isChanged: false);
                    tabPage.Tag = sqlFile;
                    sqlFile.IsChanged = false;
                    tabPage.Text = sqlFile.DisplayName;
                    textBox.Text = sqlFile.Load();
                    sqlFile.IsChanged = false;

                    // store the complete filename in settings
                    InsertRecentFileLists(openFileDialog.FileName);
                    Settings.Save();

                    // Load recent files into ToolStripMenu
                    LoadRecentFilesIntoToolStripItems();

                }
            }
            // update Tab Caption
            tabPage.ToolTipText = ((SqlFile)tabPage.Tag).FullName;
            tabPage.Text = ((SqlFile)tabPage.Tag).DisplayName;

        }