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These are my SQL tables CONSTRAINT [FK_regLloji_regModeli] FOREIGN KEY([Shifra_Mod]改變ComboBox中選定的項目
![These are my SQL tables CONSTRAINT [FK_regLloji_regModeli] FOREIGN KEY([Shifra_Mod]](https://i.stack.imgur.com/Mdybs.png){kind=link}
，當我在組合框讀條0001的結果是OK：
當我嘗試另一篇文章像技術我看到這個錯誤： 
這是我從數據庫中讀取數據的代碼。我有問題只與組合框
private void txtShifra_KeyDown(object sender, KeyEventArgs e)
{
using (SqlConnection connection = new SqlConnection(connstring))
{
SqlCommand command1 =
new SqlCommand("select * from regLloji where Shifra_Lloji = '" + txtShifra.Text + "'", connection);
connection.Open();
SqlDataReader read1 = command1.ExecuteReader();
while (read1.Read())
{
txtShifra.Text = (read1["Shifra_Lloji"].ToString());
txtLloji.Text = (read1["Lloji"].ToString());
string combobox = (string)(read1["Shifra_Mod"]);
comboBox1.SelectedValue = combobox;
}
read1.Close();
}}
這裏是填充組合框代碼：
this.comboBox1.DataBindings.Add(
new System.Windows.Forms.Binding("SelectedValue",
this.regModeliBindingSource, "Shifra_Mod", true));
this.comboBox1.DataSource = this.regModeliBindingSource;
this.comboBox1.DisplayMember = "Modeli"; this.comboBox1.ValueMember = "Shifra_Mod";
組合框的樣式設置爲DropDownList。
完整的Windows表單代碼：
using System;
using System.Data;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace PROJECT1
{
public partial class regLlojet : Form
{
public string connstring = @"Data Source=tcp:10.0.0.1;Initial Catalog=Database;User ID=user;Password=pass;MultipleActiveResultSets=true;";
Timer timer1 = new Timer();
public regLlojet()
{
InitializeComponent();
if (String.IsNullOrEmpty(txtShifra.Text))
{
txtLloji.Enabled = false;
comboBox1.Enabled = false;
btnKonfirm.Enabled = false;
btnDelete.Enabled = false;
}
timer1.Interval = 2000; //10 sec interval
timer1.Tick += new EventHandler(Tick); //Tick event
}
private void Tick(object sender, EventArgs e)
{
lblRuajtja.Text = "";
timer1.Stop(); //Stop timer after tick once
}
protected override bool ProcessDialogKey(Keys keyData)
{
if (Form.ModifierKeys == Keys.None && keyData == Keys.Escape)
{
this.Close();
return true;
}
return base.ProcessDialogKey(keyData);
}
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
//Press Key
if (keyData == Keys.F2)
{
Anulo();
}
else if (keyData == Keys.F8)
{
btnKonfirm.PerformClick();
}
return base.ProcessCmdKey(ref msg, keyData);
}
public void Anulo()
{
//Clean Textbox
Action<Control.ControlCollection> func = null;
func = (controls) =>
{
foreach (Control control in controls)
if (control is TextBox)
(control as TextBox).Clear();
else
func(control.Controls);
this.comboBox1.Text = null;
};
func(Controls);
txtLloji.Enabled = false;
comboBox1.Enabled = false;
btnKonfirm.Enabled = false;
btnDelete.Enabled = false;
}
private void btnKonfirm_Click(object sender, EventArgs e)
{
//Create new user
if (String.IsNullOrEmpty(txtLloji.Text))
{
MessageBox.Show("Plotesoni fushen Lloji", "Error", MessageBoxButtons.OK, MessageBoxIcon.Warning);
}else if (String.IsNullOrEmpty(comboBox1.Text))
{
MessageBox.Show("Plotesoni fushen Modeli", "Error", MessageBoxButtons.OK, MessageBoxIcon.Warning);
}
else
{
SqlConnection con1 = new SqlConnection(connstring);
SqlCommand cmd1 = new SqlCommand();
try
{
if (con1.State == ConnectionState.Closed)
{
con1.Open();
}
//Insert Data in Elk_KonfigGrp
cmd1 = new SqlCommand("sp_Insert_Lloji", con1);
cmd1.Parameters.AddWithValue("@Action", "INSERT");
cmd1.CommandType = CommandType.StoredProcedure;
cmd1.Parameters.AddWithValue("@Shifra_Lloji", txtShifra.Text);
cmd1.Parameters.AddWithValue("@Lloji", txtLloji.Text);
cmd1.Parameters.AddWithValue("@Shifra_Mod", comboBox1.SelectedValue);
int conn = cmd1.ExecuteNonQuery();
if (conn == 0)
{
//Not updated.
lblRuajtja.Text = "Lloji i vetures nuk u ruajt.";
timer1.Start(); //start timer
}
else
{
//Updated.
lblRuajtja.Text = "Lloji i vetures u ruajt me sukses..";
timer1.Start(); //start timer
}
}
catch (Exception)
{// do exception handling here
lblRuajtja.Text = "Lloji i vetures nuk u ruajt CATCH.";
timer1.Start(); //start timer
}
con1.Close();
Anulo();
}
}
private void btnDelete_Click(object sender, EventArgs e)
{
//Delete
SqlConnection con3 = new SqlConnection(connstring);
SqlCommand cmd3 = new SqlCommand();
try
{
if (con3.State == ConnectionState.Closed)
{
con3.Open();
}
{
//Delete Data in Elk_KonfigEdin
cmd3 = new SqlCommand("sp_Insert_Lloji", con3);
cmd3.CommandType = CommandType.StoredProcedure;
cmd3.Parameters.AddWithValue("@Action", "DELETE");
cmd3.Parameters.AddWithValue("@Shifra_Lloji", txtShifra.Text);
cmd3.Parameters.AddWithValue("@Lloji", txtLloji.Text);
cmd3.Parameters.AddWithValue("@Shifra_Mod", comboBox1.SelectedValue);
int conn3 = cmd3.ExecuteNonQuery();
if (conn3 == 0)
{
//Not updated.
lblRuajtja.Text = "Lloji i vetures nuk eshte fshir.";
timer1.Start(); //start timer
}
else
{
//Updated.
lblRuajtja.Text = "Lloji i vetures eshte fshir me sukses.";
timer1.Start(); //start timer
}
}
}
catch (Exception)
{// do exception handling here
lblRuajtja.Text = "Lloji i vetures nuk eshte fshir.";
timer1.Start(); //start timer
}
con3.Close();
Anulo();
}
private void btnAnulo_Click(object sender, EventArgs e)
{
Anulo();
}
private void btnDalje_Click(object sender, EventArgs e)
{
this.Close();
}
private void txtShifra_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
if (((TextBox)sender).Text.Length < 5)
{
e.SuppressKeyPress = true;
string str = "";
int addZeroes = 4 - txtShifra.Text.Length;
for (int i = 0; i < addZeroes; i++)
{
str += "0";
}
string val = txtShifra.Text;
txtShifra.Text = "";
txtShifra.Text = str + val;
txtLloji.Enabled = true;
comboBox1.Enabled = true;
txtLloji.Focus();
if (txtLloji.Enabled == true)
{
btnKonfirm.Enabled = true;
btnDelete.Enabled = true;
}
else
{
btnKonfirm.Enabled = false;
btnDelete.Enabled = false;
}
}
else
{
e.SuppressKeyPress = true;
txtLloji.Enabled = true;
comboBox1.Enabled = true;
txtLloji.Focus();
if (txtLloji.Enabled == true)
{
btnKonfirm.Enabled = true;
btnDelete.Enabled = true;
}
else
{
btnKonfirm.Enabled = false;
btnDelete.Enabled = false;
}
}
using (SqlConnection connection = new SqlConnection(connstring))
{
SqlCommand command1 =
new SqlCommand("select * from regLloji where Shifra_Lloji = '" + txtShifra.Text + "'", connection);
connection.Open();
SqlDataReader read1 = command1.ExecuteReader();
while (read1.Read())
{
txtShifra.Text = (read1["Shifra_Lloji"].ToString());
txtLloji.Text = (read1["Lloji"].ToString());
string combobox = (string)(read1["Shifra_Mod"]);
comboBox1.SelectedValue = combobox;
}
read1.Close();
}
}
private void txtLloji_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
e.SuppressKeyPress = true;
comboBox1.Focus();
}
}
private void comboBox1_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
e.SuppressKeyPress = true;
btnKonfirm.Focus();
}
}
private void txtShifra_KeyPress(object sender, KeyPressEventArgs e)
{
if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar))
{
e.Handled = true;
}
}
private void regLlojet_Load(object sender, EventArgs e)
{
this.regModeliTableAdapter.Fill(this.modeliVeturesDataSet.regModeli);
this.comboBox1.Text = null;
}
}
}
什麼是「組合框」？ –
它從上面的行讀取的字符串 – BugFinder
問題是我想選擇組合框中的值，因爲它是在數據庫中 我添加了更多圖片的另一篇文章，因爲不會允許我在原始文章中張貼超過2 – aarriiaann