如何在combox的选择值之后获取文本框中的值？ [英] How to get values in textboxes after selection value of combox?
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问题描述
how can i get data in textboxes from database if my combobox selected values are from table1 and the values i want to get in textboxes are from table2 ?
i我在所有文本框中只获得1个主题的名称我希望所有主题在从combox中选择课程后显示在文本框中
我尝试过：
i am getting name of just 1 subject in all textboxes i want all subject to show in textboxes after selecting class from combox
What I have tried:
private void Result_Load(object sender, EventArgs e)
{
string query = "SELECT class_id , class_name FROM class";
fillcombo(comboBox3, query, "class_name", "class_id");
// comboBox3_SelectedIndexChanged(null, null);
}
public void fillcombo(ComboBox combo, string query, string displayMember, string valueMember)
{
command = new SqlCommand(query, con);
adapter = new SqlDataAdapter(command);
table = new DataTable();
adapter.Fill(table);
combo.DataSource = table;
combo.DisplayMember = displayMember;
combo.ValueMember = valueMember;
}
private void comboBox3_SelectedIndexChanged(object sender, EventArgs e)
{
con.Open();
int val;
Int32.TryParse(comboBox3.SelectedValue.ToString(), out val);
//string query = "SELECT sub_name, class_id FROM subject WHERE class_id = " + val;
string query = "SELECT dbo.Subject.sub_name, dbo.Class.class_name FROM dbo.Class full JOIN dbo.Subject ON dbo.Class.class_id = dbo.Subject.class_id where Class.class_id="+val;
//string query = "SELECT sub_name FROM subject";
SqlCommand command = new SqlCommand(query, con);
using (var reader = command.ExecuteReader())
{
//SqlDataReader sdr = command.ExecuteReader();
if (reader.Read())
{
textBox1.Text = reader["sub_name"].ToString();
textBox2.Text = reader["sub_name"].ToString();
textBox3.Text = reader["sub_name"].ToString();
textBox4.Text = reader["sub_name"].ToString();
textBox5.Text = reader["sub_name"].ToString();
textBox7.Text = reader["sub_name"].ToString();
textBox8.Text = reader["sub_name"].ToString();
textBox9.Text = reader["sub_name"].ToString();
textBox10.Text = reader["sub_name"].ToString();
textBox11.Text = reader["sub_name"].ToString();
}
reader.Close();
}
con.Close();
}
推荐答案
您将同一列（sub_name）移动到不同的文本框。
您需要：
1）访问不同列时使用不同的名称
2）如果需要，读取多行...看起来像一个连接。
You keep moving the same column ("sub_name") to the different text boxes.
You need to:
1) Use different names when accessing different columns
2) Read more than one row, if needed ... looks like a join.
取一个计数器变量并依赖计数器值将主题名称分配给文本框
如下例所示
Int32 rowcounter = 0;
using（var reader = command.ExecuteReader（））
{
// SqlDataReader sdr = command.ExecuteReader（）;
if（ reader.Read（））
{
if（rowcounter == 0）
{
textBox1.Text = reader [sub_name]。ToString（）;
}
else if（rowcounter = = 1 ）
{
textBox2.Text = reader [sub_name]。ToString（）;
}
否则if（rowcounter == 2）
{
textBox3.Text = reader [sub_name]。ToString（）;
}
else if（rowcounter == 3）
{
textBox4.Text = reader [sub_name]。ToString（）;
}
else if（rowcounter == 4）
{
textBox5.Text = reader [sub_name]。 ToString（）;
}
else if（rowcounter == 5）
{
textBox6.Text = reader [sub_name]。ToString（）;
}
。
。
。
rowcounter ++;
}
reader.Close（）;
}
con.Close（）;
}
Take one counter variable and depending counter value assign subject name to textbox
as example below
Int32 rowcounter = 0;
using (var reader = command.ExecuteReader())
{
//SqlDataReader sdr = command.ExecuteReader();
if (reader.Read())
{
if(rowcounter == 0 )
{
textBox1.Text = reader["sub_name"].ToString();
}
else if(rowcounter == 1 )
{
textBox2.Text = reader["sub_name"].ToString();
}
else if(rowcounter == 2 )
{
textBox3.Text = reader["sub_name"].ToString();
}
else if(rowcounter == 3 )
{
textBox4.Text = reader["sub_name"].ToString();
}
else if(rowcounter == 4 )
{
textBox5.Text = reader["sub_name"].ToString();
}
else if(rowcounter == 5 )
{
textBox6.Text = reader["sub_name"].ToString();
}
.
.
.
rowcounter++;
}
reader.Close();
}
con.Close();
}
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