查询表达式中的C＃语法错误（缺少运算符）

Question

我在cmd.ExecuteNonQuery()上收到此错误...我认为在cmd.CommandText上我错了...

查询表达式'Nr_Crt ='1'和Varsta'3'和KG'2'以及Specie'Iepure'和Risc'Nu'和Tip1'Diurn'和Tip2'Carnivor'的语法错误（缺少运算符）。

    private void button2_Click_1(object sender, EventArgs e)
        {
            if (txtNr_Crt.Text != " " & txtVarsta.Text != " " & txtKG.Text != " " & txtSpecie.Text != " " & txtRisc.Text != " " & txtTip1.Text != " " & txtTip1.Text != " " & txtTip2.Text != "")
            {

                cn.Open();
                cmd.CommandText = "DELETE from Animale Where Nr_Crt='" + txtNr_Crt.Text + "' and Varsta '" + txtVarsta.Text + "' and KG '" + txtKG.Text + "' and Specie '" + txtSpecie.Text + "' and Risc'" + txtRisc.Text + "' and Tip1 '" + txtTip1.Text + "' and Tip2 '" + txtTip2.Text + "'";
                cmd.ExecuteNonQuery();
                cn.Close();

                loaddata();

                txtNr_Crt.Text = "";
                txtVarsta.Text = "";
                txtKG.Text = "";
                txtSpecie.Text = "";
                txtSex.Text = "";
                txtRisc.Text = "";
                txtTip1.Text = "";
                txtTip2.Text = "";
            }
        }

Answer 1

您的代码容易受到SQL注入的攻击，我会解决此问题。

问题是您在每个后继and都缺少= ：

cn.Open();

cmd.Parameters.AddWithValue("@Nr_Crt", txtNr_Crt.Text);  
cmd.Parameters.AddWithValue("@Varsta", txtVarsta.Text);  
cmd.Parameters.AddWithValue("@KG", txtKG.Text);  
cmd.Parameters.AddWithValue("@Specie", txtSpecie.Text);  
cmd.Parameters.AddWithValue("@Risc", txtRisc.Text);  
cmd.Parameters.AddWithValue("@Tip1", txtTip1.Text);  
cmd.Parameters.AddWithValue("@Tip2", txtTip2.Text);  
cmd.CommandText = "DELETE from Animale Where Nr_Crt= @Nr_Crt and Varsta = @Varsta and KG = @KG and Specie = @Specie and Risc = @Risc and Tip1 = @Tip1 and Tip2 = @Tip2";

cmd.ExecuteNonQuery();
cn.Close();

这应该可以解决（以及SQL注入风险）

Answer 2

您的查询是错误的。 您缺少=比较列时

cmd.CommandText = "DELETE from Animale Where Nr_Crt='" + txtNr_Crt.Text + "' and Varsta='" + txtVarsta.Text + "' and KG='" + txtKG.Text + "' and Specie='" + txtSpecie.Text + "' and Risc='" + txtRisc.Text + "' and Tip1='" + txtTip1.Text + "' and Tip2='" + txtTip2.Text + "'";

Answer 3

foreach(Control ctrl in this.Controls)
{
    if (ctrl is TextBox)
    {
      ctrl.text="";
    }
}

为了一次清理所有文本框:)，您可以创建一个在需要时执行该方法的方法