我可以使用隐藏的 DataGridView 列来管理 SQL Server VarBinary 字段吗？

Question

我有一个表，我想在字段中存储一个字节数组。字节数组大约是 20 字节（160 位）的关键数据。

我正在使用多个DataGridView 来管理此表和此应用程序的其他表。我目前有几个例程允许我提供 SQL 选择字符串，DataGridView 允许用户编辑数据。

private void InitializeUsersDataGrid()
{
  string sql = "SELECT UserId, Enabled, AccessLevel, Name, KeyValue FROM Users";

  DataGridViewIntialize(dgvUsers, sql);
  dgvUsers.Columns[fdKeyValue].Visible = false;
}

private void DataGridViewIntialize(DataGridView dataGridView, string sql)
{
  dataGridViewInUse = dataGridView; // This is the current DataGridView
  OleDbConnection oleDbConnection = new OleDbConnection(txtConnectionString.Text);
  dataAdapter = new OleDbDataAdapter(sql, oleDbConnection);
  OleDbCommandBuilder commandBuilder = new OleDbCommandBuilder(dataAdapter);  //Creates SQL commands for IUD

  dataTable = new DataTable();
  dataTable.Locale = System.Globalization.CultureInfo.InvariantCulture;

  dataAdapter.Fill(dataTable);
  bindingSource1.DataSource = dataTable;

  dataGridView.DataSource = bindingSource1;

  // Resize the DataGridView columns to fit the newly loaded content.
  dataGridView.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells);
  AddDeleteRefreshContextMenu(dataGridView);
}

我有一个保存按钮，它提供验证然后调用TableSave。

private void TableSave()
{
  // Update the database with the user's changes.
  try {
    dataAdapter.Update((DataTable)bindingSource1.DataSource);
  }
  catch (Exception ex) {
    MessageBox.Show(ex.Message);
  }
}

当我将varbinary 字段添加到表中时，它在DataGridView 中显示为损坏的位图图像。这一点我并不关心，因为无论如何我都不打算展示它。

当我尝试为调用分配一个新的字节数组时，它会生成一个 DataGridView 默认错误对话框。

/// <summary>
/// Change the password hash for the selected login
/// </summary>
/// <param name="e"></param>
void ChangePassword( DataGridViewCellEventArgs e)
{
  // Request a new password with confirmation
  fPassword form = new fPassword();
  form.Confirm = true;
  DialogResult dr = form.ShowDialog();
  if (dr == DialogResult.OK) {
    // Combine the UserID with the password to generate a new key
    byte[] salt;
    byte[] key;
    string p = dgvUsers.Rows[e.RowIndex].Cells["UserId"].Value + form.Value;
    Data.PBK2DF2Hash.GenerateSaltAndKey(p, out salt, out key);
    if (dgvUsers.Rows[e.RowIndex].Cells[fdKeyValue].ValueType == key.GetType()) {
      // We do get this far Error occurs on the assignment in the next line
      dgvUsers.Rows[e.RowIndex].Cells[fdKeyValue].Value = key;
    } 
  }
}

DataGridView 默认错误对话框

DataGridView 出现以下异常：System.ArgumentException: Parameter is not valid.
在 System.Drawing.Image.FromStream（流流，布尔 使用EmbeddedColorManagement，布尔验证图像数据） 在 System.Drawing.ImageConverter.ConvertFrom(ITypeDescriptorContext 上下文、CultureInfo 文化、对象值） 在 System.Windows.Forms.Formatter.FormatObjectInternal（对象值，类型 targetType, TypeConverter sourceConverter, TypeConverter targetConverter, String formatString, IFormatProvider formatInfo, 对象格式化 NullValue) 在 System.Windows.Forms.Formatter.FormatObject（对象值，类型 targetType, TypeConverter sourceConverter, TypeConverter targetConverter, String formatString, IFormatProvider formatInfo, 对象格式化NullValue，对象dataSourceNullValue） 在 System.Windows.Forms.DataGridViewCell.GetFormattedValue（对象值， Int32 rowIndex, DataGridViewCellStyle& cellStyle, TypeConverter valueTypeConverter, TypeConverter 格式化ValueTypeConverter, DataGridViewDataErrorContexts 上下文）

要替换此默认对话框，请处理 DataError 事件。

似乎与CellFormatting 有关，但我不知道如何将其关闭。

添加这段代码提供了一个带有此错误消息的更简单的对话框：

System.FormatException：单元格的格式化值类型错误。

private void dgvUsers_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
{
  DataGridViewColumn c = dgvUsers.Columns[fnKeyValue];
  if (c != null) {
    if (e.ColumnIndex == c.Index) {
      if (e.Value != null) {
        e.FormattingApplied = true;
      }
      else
        e.FormattingApplied = false;
    }
  }
}

更新 #1 - 使用 Ivan Stoev 建议方法的附加代码，并显示了我用来请求更改密码的按钮单元。它还增加了保存盐值。

此时的问题是，当我点击更改密码按钮时，我可以打开我的密码对话框，获取密码。生成盐和键，将其保存到该行盐和键值的数据网格单元格中。

如果我执行TableSave()（参见前面的代码），除非我在网格中的不同行上单击鼠标，否则这些字段不在 SQL Server 表中。该操作似乎表明该行已脏，然后保存将起作用。

我还可以在更改密码之前或之后更改用户可见的字段之一，该行将保存。

private void InitializeUsersDataGrid()
{
  string sql = "SELECT UserId, Enabled, AccessLevel, Name, Salt, KeyValue FROM Users";

  AddAccessLevelColumn(dgvUsers);  //Add column if needed
  AddPasswordChangeColumn(dgvUsers);
  DataGridViewIntialize1(dgvUsers, sql);
  dgvUsers.Columns[UsersFieldName.fdAccessLevel].Visible = false;  //Hide the raw column from the database

  MoveAccessLevelColumn(dgvUsers, AccessLevelComboBoxColumn, AccessLevelColumnPosition);
  MoveAccessLevelColumn(dgvUsers, PasswordButtonColumn, PasswordColumnPosition);
}

private void DataGridViewIntialize1(DataGridView dataGridView, string sql)
{
  dataGridViewInUse = dataGridView; // This is the current DataGridView
  OleDbConnection oleDbConnection = new OleDbConnection(txtConnectionString.Text);
  dataAdapter = new OleDbDataAdapter(sql, oleDbConnection);
  OleDbCommandBuilder commandBuilder = new OleDbCommandBuilder(dataAdapter);  //Creates SQL commands for IUD

  dataTable = new DataTable();
  dataTable.Locale = System.Globalization.CultureInfo.InvariantCulture;

  dataAdapter.Fill(dataTable);
  dataTable.Columns[Data.UsersFieldName.fdSalt].ColumnMapping = MappingType.Hidden;
  dataTable.Columns[Data.UsersFieldName.fdKey].ColumnMapping = MappingType.Hidden;
  bindingSource1.DataSource = dataTable;

  dataGridView.DataSource = bindingSource1;

  // Resize the DataGridView columns to fit the newly loaded content.
  dataGridView.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells);
  AddDeleteRefreshContextMenu(dataGridView);
}

private void AddPasswordChangeColumn(DataGridView dataGridView)
{
  // This column will remain unless manually removed, so it only needs to be added
  // the first time the DVG is initialized.

  if (dataGridView.Columns[PasswordButtonColumn] == null) {
    // creating new ComboBoxCell Column
    DataGridViewButtonColumn btnColumn = new DataGridViewButtonColumn();
    btnColumn.Text = "Change Password";
    btnColumn.HeaderText = "Change Password";
    btnColumn.UseColumnTextForButtonValue = true;
    btnColumn.Name = PasswordButtonColumn;
    btnColumn.FlatStyle = FlatStyle.Popup;
    dataGridView.Columns.Insert(0, btnColumn);
    // Add a CellClick handler to handle clicks in the button column.
    dataGridView.CellClick += dataGridView_CellClick;
  }
}

private void dataGridView_CellClick(object sender, DataGridViewCellEventArgs e)
{
  // Ignore clicks that are not on button cells.
  if (e.RowIndex >= 0 && e.RowIndex < dgvUsers.RowCount - 1 && e.ColumnIndex == dgvUsers.Columns[PasswordButtonColumn].Index) {
    ChangePassword(e);
  }
}

/// <summary>
/// Change the password hash for the selected login
/// </summary>
/// <param name="e"></param>
private void ChangePassword(DataGridViewCellEventArgs e)
{
  // Request a new password with confirmation
  fPassword form = new fPassword();
  form.Confirm = true;
  DialogResult dr = form.ShowDialog();
  if (dr == DialogResult.OK) {
    // Combine the UserID with the password to generate a new key
    byte[] salt;
    byte[] key;
    string p = dgvUsers.Rows[e.RowIndex].Cells[Data.UsersFieldName.fdUserId].Value + form.Value;
    Data.PBK2DF2Hash.GenerateSaltAndKey(p, out salt, out key);
    var gridRow = dgvUsers.Rows[e.RowIndex];
    var dataRow = (DataRowView)gridRow.DataBoundItem;
    var value = dataRow[Data.UsersFieldName.fdKey];
    dataRow[Data.UsersFieldName.fdSalt] = salt;  //This assignment now works
    dataRow[Data.UsersFieldName.fdKey] = key;
  }
}

更新 #2 将 'NotifyCurrectCell' Dirty 添加到 'ChangePassword' 方法会通知网格需要保存单元格而不更改 UI 中的行。

private void ChangePassword(DataGridViewCellEventArgs e)
{
  // Request a new password with confirmation
  fPassword form = new fPassword();
  form.Confirm = true;
  DialogResult dr = form.ShowDialog();
  if (dr == DialogResult.OK) {
    // Combine the UserID with the password to generate a new key
    byte[] salt;
    byte[] key;
    string p = dgvUsers.Rows[e.RowIndex].Cells[Data.UsersFieldName.fdUserId].Value + form.Value;
    Data.PBK2DF2Hash.GenerateSaltAndKey(p, out salt, out key);
    var gridRow = dgvUsers.Rows[e.RowIndex];
    var dataRow = (DataRowView)gridRow.DataBoundItem;
    var value = dataRow[Data.UsersFieldName.fdKey];
    dataRow[Data.UsersFieldName.fdSalt] = salt;  //This assignment now works
    dataRow[Data.UsersFieldName.fdKey] = key;
    dgvUsers.NotifyCurrentCellDirty(true); //Tells the UI that this row has changed and needs updating
  }
}

Answer 1

您遇到的问题是因为DataGridView 默认为byte[] 数据类型创建DataGridViewImageColumn。

这里有一些选项。

• A.将DataGridView.AutoGenerateColumns 属性设置为false 并手动创建网格列。

• B.如果您真的不需要网格中的该列，请不要尝试隐藏网格列，而不要创建网格列。但是如何实现呢？对于类属性，可以使用Browsable(false)，但这是DataTable。好吧，虽然没有记录，但可以将DataColumn.ColumnMapping 属性与MappingType.Hidden 一起用于相同的目的。

在你的情况下，删除这一行

dgvUsers.Columns[fdKeyValue].Visible = false;

在DataGridViewIntialize方法里面使用

// ...
dataAdapter.Fill(dataTable);
dataTable.Columns[fdKeyValue].ColumnMapping = MappingType.Hidden;
bindingSource1.DataSource = dataTable;
// ...

您仍然可以使用这样的基础数据源访问您的列数据

var gridRow = dgvUsers.Rows[...];
var dataRow = (DataRowView)gridRow.DataBoundItem;
var value = dataRow[fdKeyValue];