Question

c#的ComboBox从数据库取数的问题

private void cbxProducts_SelectedIndexChanged(object sender, EventArgs e)
{
conn.Open();
cbxProducts.Items.Clear();
OleDbDataAdapter adp1 = new OleDbDataAdapter("select 产品 from 产品目录", conn);
DataSet ds1 = new DataSet();
adp1.Fill(ds1, "Products");
for (int i = 0; i < ds1.Tables["Products"].Rows.Count; i++)
{
cbxProducts.Items.Add(ds1.Tables["Product"].Rows[i][0].ToString());
}
请问以上代码为什么取不到数？谢谢帮忙！
请问bomanna ，您的this.cbxProducts.ValueMember ="";//这句话是什么意思？？？虽然被注释掉了但是我还想知道，谢谢

Answer 1

private void cbxProducts_SelectedIndexChanged(object sender, EventArgs e)
{
conn.Open();
cbxProducts.Items.Clear();
OleDbDataAdapter adp1 = new OleDbDataAdapter("select 产品 from 产品目录", conn);
DataSet ds1 = new DataSet();
adp1.Fill(ds1, "Products");
this.cbxProducts .DisplayMember ="产品";//(这是显示的)
//this.cbxProducts.ValueMember ="";//这是不显示的项就是可以看成数据表中的主键一样进行判断好用的(这是实际的)
this.cbxProducts.DataSource = ds1.Table[0];
conn.close();
//以后要注意数据库打开了就不要忘记关.

Answer 2

private void cbxProducts_SelectedIndexChanged(object sender, EventArgs e)
{
conn.Open();
cbxProducts.Items.Clear();
OleDbDataAdapter adp1 = new OleDbDataAdapter("select 产品 from 产品目录", conn);
DataSet ds1 = new DataSet();
adp1.Fill(ds1, "Products");
this.cbxProducts.DataSource = ds1.Tables[0];
this.cbxProducts.DisplayMember = "产品名称";
this.cbxProducts.ValueMember = "产品ID";
conn.Close();

Answer 3

private void cbxProducts_SelectedIndexChanged(object sender, EventArgs e)
{
conn.Open();
cbxProducts.Items.Clear();
OleDbDataAdapter adp1 = new OleDbDataAdapter("select 产品 from 产品目录", conn);
DataSet ds1 = new DataSet();
adp1.Fill(ds1, "Products");
for (int i = 0; i < ds1.Tables["Products"].Rows.Count; i++)
{
cbxProducts.Items.Add(ds1.Tables["Product"].Rows[i][0].ToString());
}

你事件写错了，笨蛋！

Answer 4

放到SelectedIndexChanged事件里不是每次都要读一遍数据库？压力不小哦
你的Tables["Products"].Rows.Count是多少呢，断一下看看

Answer 5

SelectedIndexChanged?
你想要实现什么效果阿？