我正在通过 SQL 数据适配器填充 ComboBox，并且遇到了适配器带回四个表计数的问题。这很奇怪，因为数据库中只有三个表，并且它正在用适当的行填充最终表 (ds.Tables[3]) 而不是初始表 (ds.Tables[0])。
以下代码不会填充 ComboBox（注意 cboCities.DataSource（倒数第二行））：
private void Form1_Load(object sender, EventArgs e)
{
// Establishes a connection to the database.
SqlCeConnection cn = new SqlCeConnection(@"Data Source = C:\Users\user\Desktop\Projects\ParkSurvey WF\ParkSurvey WF\ParkSurvey.sdf; Persist Security Info = False; Password = *");
cn.Open();
// Gathering the names of cities from the Cities database to populate cboCities.
SqlCeCommand cmd = cn.CreateCommand();
cmd.CommandText = "SELECT CityId, Name FROM Cities ORDER BY Name ASC";
SqlCeDataAdapter da = new SqlCeDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
// Closing the connection and setting the data bindings for cboCities.
cn.Close();
cboCities.ValueMember = "CityId";
cboCities.DisplayMember = "Name";
cboCities.DataSource = ds.Tables[0];
cboCities.SelectedIndex = -1;
}
这确实会适当地填充 ComboBox（再次注意 cboCities.DataSource）：
private void Form1_Load(object sender, EventArgs e)
{
// Establishes a connection to the database.
SqlCeConnection cn = new SqlCeConnection(@"Data Source = C:\Users\user\Desktop\Projects\ParkSurvey WF\ParkSurvey WF\ParkSurvey.sdf; Persist Security Info = False; Password = *");
cn.Open();
// Gathering the names of cities from the Cities database to populate cboCities.
SqlCeCommand cmd = cn.CreateCommand();
cmd.CommandText = "SELECT CityId, Name FROM Cities ORDER BY Name ASC";
SqlCeDataAdapter da = new SqlCeDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
// Closing the connection and setting the data bindings for cboCities.
cn.Close();
cboCities.ValueMember = "CityId";
cboCities.DisplayMember = "Name";
cboCities.DataSource = ds.Tables[3];
cboCities.SelectedIndex = -1;
}
是什么导致我的 DataAdapter 带回四个表而不是 JUST Cities，为什么它填充第四个表而不是初始表？如果您需要更多代码示例来帮助我解决此问题，请告诉我。非常感谢你！