Value ComboBox更改TextBox的值在C＃

Question

您好專家我使用此代碼前段時間，是工作，但現在不工作......！它說

（轉化爲varchar值 「System.Data.DataRowView」轉換爲數據類型爲int失敗時）

代碼下拉框中選擇價值變動文本框與此值的詳細信息並感謝你提前。

public partial class test : Form 
{ 

    SqlConnection cn = new SqlConnection("Server=AMEER;DataBase=custemer_net;Integrated security=true"); 
    SqlDataAdapter da; 
    DataTable dt = new DataTable(); 
    DataTable dttt = new DataTable(); 
    public test() 
    { 
     InitializeComponent(); 
     da = new SqlDataAdapter("Select *from subscrbtion ", cn); 
     da.Fill(dt); 
     comboBox1.DisplayMember = "name"; 
     comboBox1.ValueMember = "id"; 
     comboBox1.DataSource = dt; 

    } 

    private void comboBox1_SelectedIndexChanged(object sender, EventArgs e) 
    { 
     da = new SqlDataAdapter("select * from subscrbtion where id='" + comboBox1.SelectedValue + "'", cn); 
     da.Fill(dttt); 
     textBox1.Text = dttt.Rows[0]["phone"].ToString(); 
    } 

Answer 1

我認爲你必須在你的SqlDataAdapter故障：

new SqlDataAdapter("select * from subscrbtion where id='" + comboBox1.Text + "'", cn); 

應該

new SqlDataAdapter("select * from subscrbtion where id='" + comboBox1.SelectedValue + "'", cn); 

的SelectedValue將指向標識，你ValueMember下宣佈。

附加：設置您的組合框的數據源，宣佈其數據/值成員後：

comboBox1.DisplayMember = "name"; 
comboBox1.ValueMember = "id"; 
comboBox1.DataSource = dt; 

做根據你的代碼更改：

public test() 
{ 
    InitializeComponent(); 

    using(SqlConnection cn = new SqlConnection("Server=AMEER;DataBase=custemer_net;Integrated security=true")) 
    { 
     var adapter = new SqlDataAdapter("Select *from subscrbtion ", cn); 
     adapter.Fill(dt); 
    } 
    comboBox1.DisplayMember = "name"; 
    comboBox1.ValueMember = "id"; 
    comboBox1.DataSource = dt; 
} 

private void comboBox1_SelectedIndexChanged(object sender, EventArgs e) 
{ 
    //for testing 
    MessageBox.Show(comboBox1.SelectedValue.ToString()); 
    // 

    //clear the datatable dttt 
    dttt.Clear();     //<----------THIS SHOULD BE YOUR NEW SOLUTION 

    //refill the datatable with the new information 
    using(SqlConnection cn = new SqlConnection("Server=AMEER;DataBase=custemer_net;Integrated security=true")) 
    { 
     var adapter = new SqlDataAdapter("select * from subscrbtion where id='" + comboBox1.SelectedValue + "'", cn); 
     adapter.Fill(dttt); 
    } 
    //for testing 
    MessageBox.Show(dttt.Rows.Count.ToString()); 
    // 

    //show the data inside the textbox. 
    textBox1.Text = dttt.Rows[0]["phone"].ToString(); 
} 

讓我知道了消息框下降

編輯： 根據msdn：SqlDataAdapter.Fill（）方法ADDS dat內的值凌辱。 ==>這個課程意味着爲什麼測試消息框總是隨着行增加。

我在上面的代碼中添加了值，希望這有助於幫助