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我有一个用 C# 2010 Express 开发的程序，它的表单由一个 DataGridView 组成，下面有一个单独的单元格编辑字段。选择一行（在其左端单击）时，该行中的值将复制到编辑字段中。进行了更改，并单击了“记忆交易”按钮。新值出现在 DataGridView 中。如果表单随后关闭并重新打开（处理并重新加载），则显示原始值，而不是新值。显然数据库记录没有更新。

如果重复上述过程，除了在关闭表单之前再次选择记录并再次单击“记忆事务”按钮之外，该值将存储在数据库中。当窗体关闭然后重新打开时，会出现新值。

显然，所需的行为是在第一次单击“记忆事务”按钮时立即将值存储在数据库中。

以下声明出现在表单类的顶部：

    DataTable _dt;
    SqlDataAdapter _adapter;

方法 load_DataGridView() 如下所示。请注意，适配器的更新、删除和插入查询是通过调用它们各自的 SqlCommandBuilder 的 GetXXXCommand() 方法构建的。调试期间的断点表明这些已正确填充。

    private void load_dataGridView()
    {
        DataTable dt = new DataTable();
        _dt = dt;
        SqlConnection dbconn = new SqlConnection(dbq.connectionString);
        dbconn.Open();
        string qstr = @"SELECT transaction_id
    , 0 as pay
    , m.has_splits
    , m.Num
    , m.Type
    , m.last_date
    , m.next_date
    , m.Payee
    , m.Memo
    , m.Tax_Category
    , m.Amount
    , m.Clr
    , m.Initials
    , m.sales_tax_paid
    , m.from_institution_id as FromInstitutionID
    , m.from_institution as FromInstitution
    , m.from_account_id as FromAccountID
    , m.from_account as FromAccount
    , m.from_envelope_id as FromEnvelopeID
    , m.from_envelope as FromEnvelope
    , m.to_institution_id as ToInstitutionID
    , m.to_institution as ToInstitution
    , m.to_account_id as ToAccountID
    , m.to_account as ToAccount
    , m.to_envelope_id as ToEnvelopeID
    , m.to_envelope as ToEnvelope
    , m.frequency
    FROM memorized m
    ";
        SqlDataAdapter adapter = new SqlDataAdapter(qstr,dbconn);
        SqlCommandBuilder scb = new SqlCommandBuilder(adapter);
        adapter.UpdateCommand = new SqlCommandBuilder(adapter).GetUpdateCommand();
        adapter.DeleteCommand = new SqlCommandBuilder(adapter).GetDeleteCommand();
        adapter.InsertCommand = new SqlCommandBuilder(adapter).GetInsertCommand();
        _adapter = adapter;
        _adapter.Fill(_dt);
        build_dgv_columns(Properties.Settings.Default.currentInstitutionId,
        Properties.Settings.Default.currentAccountId);
        memorizedDataGridView.DataSource = _dt;
    }

点击 Memorize Transaction 按钮时调用的代码如下：

    private void bnMemorizeTx_Click(object sender, EventArgs e)
    {
        if (_newTx)
        {
            _currentTxRow = _dt.Rows.Count;
            _dt.Rows.Add();
            _newTx = false;
        }
        else
        {
            _currentTxRow = memorizedDataGridView.SelectedRows[0].Index;
        }
        populateRowFromFields(memorizedDataGridView.Rows[_currentTxRow]);
        memorizedDataGridView.Refresh();
        memorizedDataGridView.ClearSelection();
        //grid shows new value with no rows selected at this point, row is "dirty"
        try
        {
            _adapter.Update(_dt);
        }
        catch (SqlException e1)
        {
            MessageBox.Show(e1.Message + e1.InnerException, "Error Thrown",MessageBoxButtons.OK);
        }
        reset_transaction_fields();
    }

从来没有抛出异常。我怀疑将数据从 DataGridView 拉出到编辑字段中，然后以某种方式再次将其写回的操作会以某种方式使用 _adapter.Update(_dt) 命令检测行已更改的能力，因此当它被调用时，它不会不更新任何东西。然后在第二次尝试时，当重新选择行（显示新值）但没有进行编辑更改时，它确实有效。不知何故，即使新值出现在网格中，就像尚未提交更改并且必须重新选择该行才能发生这种情况。

populateRowFromFields 方法如下，使用单元格索引的列名引用将编辑字段中的值写回行中的单元格值：

            private void populateRowFromFields(DataGridViewRow dgvr)
    {
        dgvr.Cells["Num"].Value = tbRefNum.Text;
        dgvr.Cells["Type"].Value = cbType.GetItemText(cbType.SelectedItem);
        dgvr.Cells["last_date"].Value = dtpLastPaid.Value.ToShortDateString();
        dgvr.Cells["next_date"].Value = dtpNextPay.Value.ToShortDateString();
        dgvr.Cells["Payee"].Value = tbPayee.Text;
        dgvr.Cells["Amount"].Value = tbAmount.Text;
        dgvr.Cells["FromInstitutionID"].Value = cbFromInst.GetItemText(cbFromInst.SelectedValue); // fromInst
        dgvr.Cells["FromInstitution"].Value = cbFromInst.GetItemText(cbFromInst.SelectedItem); // fromAcct
        dgvr.Cells["FromAccountID"].Value = cbFromAcct.GetItemText(cbFromAcct.SelectedValue); // fromEnv
        dgvr.Cells["FromAccount"].Value = cbFromAcct.GetItemText(cbFromAcct.SelectedItem); // fromInst
        dgvr.Cells["FromEnvelopeID"].Value = cbFromEnv.GetItemText(cbFromEnv.SelectedValue); // fromAcct
        dgvr.Cells["FromEnvelope"].Value = cbFromEnv.GetItemText(cbFromEnv.SelectedItem); // fromEnv
        if ((cbType.GetItemText(cbType.SelectedItem) == "+iTx") || (cbType.GetItemText(cbType.SelectedItem) == "-iTx") || (cbType.GetItemText(cbType.SelectedItem) == "+eTx") || (cbType.GetItemText(cbType.SelectedItem) == "-eTx")) 
        {
            dgvr.Cells["ToInstitutionID"].Value = cbToInst.GetItemText(cbToInst.SelectedValue); // toInst
            dgvr.Cells["ToInstitution"].Value = cbToInst.GetItemText(cbToInst.SelectedItem); // toInst
            dgvr.Cells["ToAccountID"].Value = cbToAcct.GetItemText(cbToAcct.SelectedValue); // toAcct
            dgvr.Cells["ToAccount"].Value = cbToAcct.GetItemText(cbToAcct.SelectedItem); // toAcct
            dgvr.Cells["ToEnvelopeID"].Value = cbToEnv.GetItemText(cbToEnv.SelectedValue); // toEnv
            dgvr.Cells["ToEnvelope"].Value = cbToEnv.GetItemText(cbToEnv.SelectedItem); // toEnv
            hideTxToFields();
        }
        dgvr.Cells["Memo"].Value = tbMemo.Text;
        dgvr.Cells["Tax_Category"].Value = cbTaxCategory.GetItemText(cbTaxCategory.SelectedItem); // taxCategory
        dgvr.Cells["sales_tax_paid"].Value = cbSalesTaxPaid.GetItemText(cbSalesTaxPaid.SelectedItem); // salesTaxPaid
        dgvr.Cells["Clr"].Value = "U";
        dgvr.Cells["Initials"].Value = cbBy.GetItemText(cbBy.SelectedItem); // by
        dgvr.Cells["frequency"].Value = cbFrequency.GetItemText(cbFrequency.SelectedItem); // frequency
    }

帮助！这让我发疯！

4

1 回答 1

0

最简单的选择是通过 a 为网格和编辑控件使用数据绑定BindingSource，例如

private SqlConnection connection;
private SqlDataAdapter adapter;
private SqlCommandBuilder builder;
private DataTable table;

private void Form1_Load(object sender, EventArgs e)
{
    connection = new SqlConnection("connection string here");
    adapter = new SqlDataAdapter("SELECT * FROM Person", connection);
    builder = new SqlCommandBuilder(adapter);
    table = new DataTable();

    adapter.Fill(table);
    bindingSource1.DataSource = table;
    dataGridView1.DataSource = bindingSource1;
    givenNameTextBox.DataBindings.Add("Text", bindingSource1, "GivenName");
    familyNameTextBox.DataBindings.Add("Text", bindingSource1, "FamilyName");
}

private void addButton_Click(object sender, EventArgs e)
{
    bindingSource1.AddNew();
}

private void deleteButton_Click(object sender, EventArgs e)
{
    bindingSource1.RemoveCurrent();
}

private void saveButton_Click(object sender, EventArgs e)
{
    bindingSource1.EndEdit();
    adapter.Update(table);
}
于 2014-08-02T03:07:55.243 回答