`SqlConnection con = new SqlConnection（“Data Source = DESKTOP-NGRLFB4 \ SQLEXPRESS; Initial Catalog = dboo; Persist Security Info = True; User ID = sa; Password = *****”）; SqlCommand命令; SqlDataAdapter适配器; DataTable表; DataRow博士; private void Form1_Load（object sender，EventArgs e） { string query =“SELECT Going_Id，LeavingFrom FROM LeavingAndGoing”; comboBox1.DataSource = getData（query）; comboBox1.DisplayMember =“LeavingFrom”; comboBox1.ValueMember =“Going_Id”;
}
public DataTable getData(string query)
{
command = new SqlCommand(query, con);
adapter = new SqlDataAdapter(command);
table = new DataTable();
adapter.Fill(table);
return table;
}
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
int val;
Int32.TryParse(comboBox1.SelectedValue.ToString(), out val);
string query = "SELECT ID, GoingPlace, Id_Gonig FROM GoingTable Where Id_Gonig =" + val;
comboBox2.DisplayMember = "GoingPlace";
comboBox2.ValueMember = "Id_Gonig";
comboBox1.DataSource = getData(query);
}
private bool button1_Clicked = true;
private void button1_Click(object sender, EventArgs e)
{
try
{
if (comboBox2.SelectedIndex < 0)
{
MessageBox.Show("Please Enter the Place Where You Are Going");
button1_Clicked = false;
}
else
{
int val;
Int32.TryParse(comboBox2.SelectedValue.ToString(), out val);
string query1 = "SELECT ID, Departing_Time, STARTING_COUNTER, END_COUNTER, COACH_TYPE, FARE, ARRIVAL_TIME FROM Seat_Information Where SI_ID = " + val;
dataGridView1.DataSource = getData(query1);
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}`
当我尝试显示依赖于ComboBox2的datagridview1时，它只显示依赖于ComboBox1。但我希望comboBox2必须依赖 在comboBox1和datagridview1上必须依赖于comboBox1和comboBox2。 我该怎么做才能解决这个问题？