使用 DataGrid 更新访问表时出错

Question

我正在使用 DataGridView 来更新、插入或删除表中的数据。该代码可以很好地插入数据，但是在更新或删除数据或行时会出错。代码如下。

OleDbCommand sCommand;
    OleDbDataAdapter sAdapter;
    OleDbCommandBuilder sBuilder;
    DataSet sDs;
    DataTable sTable; 

    //Load Data...
    private void button1_Click(object sender, EventArgs e)
    {
        string connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source= " + Application.StartupPath + @"\Label-Data.accdb";
        string sql = "SELECT * FROM _Default";
        OleDbConnection connection = new OleDbConnection(connectionString);
        connection.Open();
        sCommand = new OleDbCommand(sql, connection);
        sAdapter = new OleDbDataAdapter(sCommand);
        sBuilder = new OleDbCommandBuilder(sAdapter);
        sDs = new DataSet();
        sAdapter.Fill(sDs, "_Default");
        sTable = sDs.Tables["_Default"];
        connection.Close();
        dataGridView1.DataSource = sDs.Tables["_Default"];
        dataGridView1.ReadOnly = true;
        button4.Enabled = false;
        dataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
    }

    //Add or Edit...
    private void button2_Click(object sender, EventArgs e)
    {
        dataGridView1.ReadOnly = false;
        button4.Enabled = true;
        button2.Enabled = false;
        button3.Enabled = false;
    }

    //Delete...
    private void button3_Click(object sender, EventArgs e)
    {
        if (MessageBox.Show("Do you want to delete this row ?", "Delete", MessageBoxButtons.YesNo) == DialogResult.Yes)
        {
            dataGridView1.Rows.RemoveAt(dataGridView1.SelectedRows[0].Index);
            sAdapter.Update(sTable);
        }
    }

    //Save...
    private void button4_Click(object sender, EventArgs e)
    {
        sAdapter.Update(sTable);
        dataGridView1.ReadOnly = true;
        button4.Enabled = false;
        button2.Enabled = true;
        button3.Enabled = true;
    }

它在 sAdapter.Update(sTable) 上给出错误； 错误是

查询表达式中的语法错误 '((ID = ?) AND ((? = 1 AND Prn IS NULL) OR (Prn = ?)) AND ((? = 1 AND _Copy IS NULL) OR (_Copy = ?) ) AND ((? = 1 AND _Item IS NULL) OR (_Item = ?)) AND ((? = 1 AND _Design IS NULL) OR (_Design = ?)) AND ((? = 1 AND Tray_No IS NULL) OR ( Tray_No = ?)) AND (('.

如何消除这个错误？

Answer 1

试试这个。

 private void button3_Click(object sender, EventArgs e)
 {
    if (MessageBox.Show("Do you want to delete this row ?", "Delete",     MessageBoxButtons.YesNo) == DialogResult.Yes)
    {
        dataGridView1.Rows.RemoveAt(dataGridView1.SelectedRows[0].Index);
       string sql="write your Delete query"
      OleDbCommand dCommand = new OleDbCommand(sql, connection);
        OleDbCommandBuilder builder = new OleDbCommandBuilder(sAdapter);
       sAdapter.DeleteCommand=dCommand
        sAdapter.Update(sTable);
    }
}

//Save...
private void button4_Click(object sender, EventArgs e)
{
     string sql="write your update query"
     OleDbCommand uCommand = new OleDbCommand(sql, connection);
     OleDbCommandBuilder builder = new OleDbCommandBuilder(sAdapter);
     sAdapter.UpdateCommand=uCommand 
    sAdapter.Update(sTable);
    dataGridView1.ReadOnly = true;
    button4.Enabled = false;
    button2.Enabled = true;
    button3.Enabled = true;
}

Answer 2

你有一些非常奇怪的字段名称，前导下划线是什么？？

但框架似乎无法自动生成插入和更新 SQL。

查看以下SO 问题，该问题描述了将您自己的 UPDATE 和 INSERT 语句添加到适配器。

或者，您可以考虑使用 VisualStudio 的 DataSet 设计器。