Ado.net组合框问题 [英] Ado.net combobox problem

问题描述

我想从火车的第一个组合框id中选择，在第二个组合框中给我一辆火车的货车（一辆货车的号码）我做了一个数据库：第一个表存储了火车id，第二个表存放了货车id + id火车外键我尝试了这个代码和它的工作但是当我选择另一个id它不会改变旅行车组合框结果



我尝试过什么：

I wanna select from first combobox id of a train and in the second combobox give me the wagon that train has (number of a wagon ) I did a database: that first table stored the train id and the second table stored wagon id + id train foreign key i tried this code and its work but when i choose another id it doesn't change the wagon combobox result

What I have tried:

adapter = new SqlDataAdapter("select * from train", cn);
            SqlCommand cmd = new SqlCommand("select * from train", cn);
            cmd.Parameters.Clear();
            adapter.Fill(ds, "train");
            
            comboBox1.DataSource = ds.Tables["train"];
            comboBox1.DisplayMember = "id";
            comboBox1.ValueMember = "id";
           
            
       adapter = new SqlDataAdapter("select  id_w  from wagon  where id='" + comboBox1.SelectedValue + "'", cn);
        
            
                adapter.Fill(ds, "wagon");

        //    adapter1.SelectCommand.Parameters.Clear();
            comboBox2.DataSource = ds.Tables["wagon"];
                comboBox2.DisplayMember = "id_w";
                comboBox2.ValueMember = "id_w";

推荐答案

您好，

ComboBox.SelectedIndexChanged 事件。

你必须通过train_id in train_SelectedIndexChanged事件。

ie，

Hello,
ComboBox.SelectedIndexChanged event occurs when the SelectedIndex property has changed.
You have to pass train_id in train_SelectedIndexChanged event.
i.e.,

private void train_SelectedIndexChanged(object sender,System.EventArgs e)
    {
       //Load the wagon_details and populate in combobox.
    }

谢谢

thanks

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