[英]C# Auto increment primary key
我已經在數據庫中將IDENTITY
設置為yes,並且每當我運行該應用程序時,該鍵都不會自動遞增,給出一個錯誤,不允許空值
private void button8_Click(object sender, EventArgs e)
{
string fname = textBox1.Text;
string lname = textBox2.Text;
//int idnum = Convert.To(textBox3.Text);
int mobnum = Convert.ToInt32(maskedTextBox1.Text);
string email = textBox4.Text;
int EdInst = comboBox1.SelectedIndex+1;
string EdLev = comboBox3.SelectedText;
string EdName = comboBox2.SelectedText;
Boolean Valid = true;
Valid = Validation(Valid);
if (Valid == true)
{
IS2Team1_TriplexDBDataSet.ApplicantRow NewApplicantRow = iS2Team1_TriplexDBDataSet1.Applicant.NewApplicantRow();
IS2Team1_TriplexDBDataSet.ApplicationRow NewApplicationRow = iS2Team1_TriplexDBDataSet1.Application.NewApplicationRow();
//NewApplicantRow.Applicant_ID = ??; // What do i do here for the ID to auto increment?
NewApplicantRow.First_Name = fname;
NewApplicantRow.Last_Name = lname;
//NewApplicantRow.ID_Number =Convert.ToInt32(textBox3.Text);
NewApplicantRow.Contact_Number = mobnum;
NewApplicantRow.Email_Address = email;
NewApplicantRow.University_ID = EdInst;
//NewApplicationRow.Application_ID = ??; // What do i do here for the ID to auto increment?
NewApplicationRow.Application_Status = "Recieved";
NewApplicationRow.Application_Date = DateTime.Today;
iS2Team1_TriplexDBDataSet1.Applicant.Rows.Add(NewApplicantRow);
iS2Team1_TriplexDBDataSet1.Application.Rows.Add(NewApplicationRow);
MessageBox.Show("Application Submitted", "Application Submitted");
this.applicantTableAdapter.Update(this.iS2Team1_TriplexDBDataSet1);
//Hide();
//Form4 frmUpdate = new Form4();
//frmUpdate.Show();
}
else if (Valid == false)
{
MessageBox.Show("Required Information Missing");
textBox1.Focus();
}
我們可以看到您正在自動遞增的視圖嗎? 應將其設置為+1或標識(1,1)
嘗試在項目中打開EDMX,單擊該列並查看屬性(F4)。 將StoreGeneratedPattern設置為Identity。
您必須在表定義中設置以下值:
樣本:不適用於實體框架 :
如果要插入新行,只需忽略您的Identity-Row,並使用以下方法獲取自動生成的Identity: @@ Identity
希望有幫助!
這是一個未測試的示例:
public static void Test()
{
int cIdentity = 0;
SqlConnection cConnection = new SqlConnection("...");
cConnection.Open();
SqlCommand cCommand = new SqlCommand("Insert INTO TestTable (Name) VALUES ('Test'); "+
"SELECT @@IDENTITY AS Ident", cConnection);
IDataReader cReader = null;
try
{
cReader = cCommand.ExecuteReader(CommandBehavior.CloseConnection);
if (cReader.Read())
{
cIdentity = cReader.GetInt32(0);
}
}
catch(Exception ex)
{
Console.WriteLine(ex);
if (cReader != null)
{
cReader.Close();
}
}
finally
{
if (cConnection != null)
{
cConnection.Close();
}
}
}
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