Question

以下是保存按钮事件处理程序：

private void btnSave_Click(object sender, EventArgs e)
{
        MySqlConnection con = new MySqlConnection(MyConnectionString);
        MySqlCommand cmd;
        con.Open();

        if (txtFN.Text != "" && txtMN.Text != "" && txtLN.Text != "" && txtAge.Text != "" && txtReligion.Text != "" && cmbGender.Text != "" && dateTimePicker1.Text != "" && cmbGrade.Text != "" && cmbStrands.Text != "" && txtPlaceBirth.Text != "" && txtHomeAddress.Text != "" && txtNameLastSchool.Text != "" && txtAddressLastSchool.Text != "")
        {
            cmd = new MySqlCommand("UPDATE tbluser set FirstName, MiddleName, LastName, Age, Religion, Gender, BirthDay, Grade, Strand, PlaceBirth, HomeAddress, NameLastSchool, AddressLastSchool) values (@fname, @mname, @Lname, @Age, @Religion, @Gender, @Birthday, @Grade, @Strand, @PlaceBirth, @HomeAddress, @NameLastSchool, @AddressLastSchool", con);
            cmd.Parameters.AddWithValue("@fname", txtFN.Text);
            cmd.Parameters.AddWithValue("@Mname", txtMN.Text);
            cmd.Parameters.AddWithValue("@Lname", txtLN.Text);
            cmd.Parameters.AddWithValue("@Age", txtAge.Text);
            cmd.Parameters.AddWithValue("@Religion", txtReligion.Text);
            cmd.Parameters.AddWithValue("@Gender", cmbGender.Text);
            cmd.Parameters.AddWithValue("@Birthday", dateTimePicker1.Text);
            cmd.Parameters.AddWithValue("@Grade", cmbGrade.Text);
            cmd.Parameters.AddWithValue("@Strand", cmbStrands.Text);
            cmd.Parameters.AddWithValue("@PlaceBirth", txtPlaceBirth.Text);
            cmd.Parameters.AddWithValue("@HomeAddress", txtHomeAddress.Text);
            cmd.Parameters.AddWithValue("@NameLastSchool", txtNameLastSchool.Text);
            cmd.Parameters.AddWithValue("@AddressLastSchool", txtAddressLastSchool.Text);
            cmd.ExecuteNonQuery();
            con.Close(); 
            MessageBox.Show("Record Updated Successfully"); 
            MessageBox.Show("Please Select Record to Update");
        }  
    }

但是代码没有按照我的意图运作。我错过了什么？

Answer 1

UPDATE DML命令使用以下语法：

UPDATE [table_name] SET [assignment_list]

或者如果您想更新现有记录：

UPDATE [table_name] SET [assignment_list] WHERE [condition]

因此，正确的语法应如下所示：

cmd = new MySqlCommand("UPDATE tbluser SET FirstName = @fname, MiddleName = @mname, LastName = @Lname, Age = @Age, Religion = @Religion, Gender = @Gender, BirthDay = @Birthday, Grade = @Grade, Strand = @Strand, PlaceBirth = @PlaceBirth, HomeAddress = @HomeAddress, NameLastSchool = @NameLastSchool, AddressLastSchool = @AddressLastSchool WHERE UserId = @UserId", con);

cmd.Parameters.AddWithValue("@fname", txtFN.Text);

// other parameters

cmd.Parameters.AddWithValue("@UserId", txtID.Text); // example for assigning record ID
cmd.ExecuteNonQuery();

呈现的查询看起来像是尝试进行INSERT查询，但由于语法不正确而导致异常。

我的更新按钮不起作用

1 个答案: