Question

我正在尝试做一个应用程序而未添加一些有关汽车送货的详细信息。我用C＃和SQL编写了代码，但是当我将数据添加到textbox，radiobutton，labels等中时，出现此错误：

System.Data.SqlClient.SqlException：'参数化查询'（@a int，@ b nvarchar（7），@ c int，@ d nvarchar（12），@ e nvarchar（10），@ f'参数'@f'，未提供。'

但是我尝试通过调试来查看它们是否采用值并且所有值都小于@f 数据库中列的长度为50或100

if (materialRadioButton5.Checked) 
{
    choose = "Excelent"; 
}
else if (materialRadioButton8.Checked) 
{
    choose = "Foarte bună"; 
}
else if (materialRadioButton7.Checked) 
{
    choose = "Bună"; 
}
else if (materialRadioButton6.Checked) 
{  
    choose = "Uzată"; 
}


if (materialRadioButton4.Checked)  
{
     chooser = "Mulţumit"; 
}
else if (materialRadioButton1.Checked)
{
     chooser = "Nemulţumit"; 
}

SqlConnection con = new SqlConnection(stringcon);
SqlCommand cmd = new SqlCommand();

con.Open();
cmd.Connection = con;

cmd.Parameters.Clear();
cmd.CommandText = "insert into returncar(id_client,fullname_client,id_team,fullname_team,rendition,condition,team_mention,customers_plesed,exp_felt,client_mention) values(@a,@b,@c,@d,@e,@f,@g,@h,@i,@j)";

cmd.Parameters.AddWithValue("@a", Convert.ToInt32(label65.Text));
cmd.Parameters.AddWithValue("@b", label67.Text);
cmd.Parameters.AddWithValue("@c", Convert.ToInt32(label66.Text));
cmd.Parameters.AddWithValue("@d", label68.Text);
cmd.Parameters.AddWithValue("@e", metroDateTime1.Text);          
cmd.Parameters.AddWithValue("@f", choose);
cmd.Parameters.AddWithValue("@g", firstname_textbox.Text);
cmd.Parameters.AddWithValue("@h", chooser);
cmd.Parameters.AddWithValue("@i", role_dropbox.selectedValue);
cmd.Parameters.AddWithValue("@j", materialSingleLineTextField1.Text);

cmd.ExecuteNonQuery();

SqlCommand cmd2 = new SqlCommand();
cmd2.Connection = con;

cmd2.Parameters.Clear();
cmd2.CommandText = "update rentcar set inchiriat=0 where id=@id";
cmd2.Parameters.AddWithValue("@id", Form2.idddloan);

cmd2.ExecuteNonQuery();

con.Close();

panel2.Visible = false;
bunifuFlatButton7.Visible = false;

radiobutton4和radiobutton1的工作方式如何，而其他的无效？...

 public string choose, chooser;

Answer 1

如果该值为null，则不添加该参数，并且您将得到提到的异常。在这种情况下，请确保检查null并通过

choose ?? Value.DBNull

参数化查询需要未提供的参数xy

1 个答案: