使用 Visual Studio 表单将信息输入数据库

Question

当我尝试将信息输入连接到我的 Visual Studio 2012 表单的数据库时遇到问题。当我开始调试时，如果我在字段中输入信息并点击提交，则没有任何内容输入到我的数据库中。如果我再次输入信息并点击提交，则信息将写入我的数据库。我不是很擅长编程，所以我使用数据源来链接我的 Visual Studio 表单和我的数据库。

这就是我的表单的样子； data form before entry

这是我输入数据后的表单； data form with information

这就是点击提交时发生的情况； confirmation message

这是第一次点击提交后的数据库； db entries after first submission

这就是我再次输入信息时发生的情况； db entries after second submission

在此之后的任何条目都将正确输入，并且一切都很好。我很困惑为什么信息（除了空条目）直到我第二次单击提交时才会输入。虽然它“在技术上有效”，但它并不完全正确。对此问题的任何帮助将不胜感激。

这是我在新客户表单中提交按钮的代码；

namespace WindowsFormsApplication2
{
public partial class frmNewCustomer : Form
{
    public frmNewCustomer()
    {
        InitializeComponent();
    }

    private void btnAddCustomer_Click(object sender, EventArgs e)
    {
        string cstFName;
        string cstLName;
        string cstAddress;
        string cstCity;
        string cstState;
        string cstZip;
        string cstPhone;
        string cstEmail;

        cstFName = cstFNameTxtBox.Text;
        cstLName = cstLNameTxtBox.Text;
        cstAddress = cstAddressTxtBox.Text;
        cstCity = cstCityTxtBox.Text;
        cstState = cstStateTxtBox.Text;
        cstZip = cstZipTxtBox.Text;
        cstPhone = cstPhoneTxtBox.Text;
        cstEmail = cstEmailTxtBox.Text;

        // exception handler for empty fields    
        if (cstFName == "")
        {
            MessageBox.Show("Please enter your first name!");
        }
        else if (cstLName == "")
        {
            MessageBox.Show("Please enter your last name!");
        }
        else if (cstAddress == "")
        {
            MessageBox.Show("Please enter your address!");
        }
        else if (cstCity == "")
        {
            MessageBox.Show("Please enter your city!");
        }
        else if (cstState == "")
        {
            MessageBox.Show("Please enter your state!");
        }
        else if (cstZip == "")
        {
            MessageBox.Show("Please enter your zip!");
        }
        else if (cstPhone == "")
        {
            MessageBox.Show("Please enter your Phone!");
        }
        else if (cstEmail == "")
        {
            MessageBox.Show("Please enter your email!");
        }
        else
        {
            MessageBox.Show("First Name: " + cstFName + " Last Name: " + cstLName + "\r\n" +
                            "Address: " + cstAddress + "\r\n" +
                            "City: " + cstCity + " State: " + cstState + " Zip: " + cstZip + "\r\n" +
                            "Phone: " + cstPhone + " Email: " + cstEmail + "\r\n" + "\r\n" +
                            "Has been added to the database.");
        }

        this.tblCustomersBindingSource.AddNew();
        this.tblCustomersBindingSource.EndEdit();
        this.tblCustomersTableAdapter.Update(this.dataSet1.tblCustomers); // Updating the DB Table
    }

    private void frmNewCustomer_Load(object sender, EventArgs e)
    {
        // TODO: This line of code loads data into the 'dataSet1.tblCustomers' table. You can move, or remove it, as needed.  Loads it into start of form!
        // this.tblCustomersTableAdapter.Fill(this.dataSet1.tblCustomers);

    }
  }
}

我意识到我的异常处理充其量是 janky，但这更多是关于创建一些将数据读取和写入数据库的表单。我感谢任何人能够提供的任何帮助，

Answer 1

如果这不是 winforms（不确定是否重要），典型的流程是这样的：

Create a connection.  
Write your insert statement.  
Do data validation.  
Submit to database.  
Commit transaction.  

试试这个：

bool shouldSubmit = false;
     // exception handler for empty fields    
            if (cstFName == "")
            {
                MessageBox.Show("Please enter your first name!");
            }
            else if (cstLName == "")
            {
                MessageBox.Show("Please enter your last name!");
            }
            else if (cstAddress == "")
            {
                MessageBox.Show("Please enter your address!");
            }
            else if (cstCity == "")
            {
                MessageBox.Show("Please enter your city!");
            }
            else if (cstState == "")
            {
                MessageBox.Show("Please enter your state!");
            }
            else if (cstZip == "")
            {
                MessageBox.Show("Please enter your zip!");
            }
            else if (cstPhone == "")
            {
                MessageBox.Show("Please enter your Phone!");
            }
            else if (cstEmail == "")
            {
                MessageBox.Show("Please enter your email!");
            }
            else
            {
                shouldSubmit = true;
                MessageBox.Show("First Name: " + cstFName + " Last Name: " + cstLName + "\r\n" +
                                "Address: " + cstAddress + "\r\n" +
                                "City: " + cstCity + " State: " + cstState + " Zip: " + cstZip + "\r\n" +
                                "Phone: " + cstPhone + " Email: " + cstEmail + "\r\n" + "\r\n" +
                                "Has been added to the database.");
            }

if(shouldSubmit)
{
            this.tblCustomersBindingSource.AddNew();
            this.tblCustomersBindingSource.EndEdit();
            this.tblCustomersTableAdapter.Update(this.dataSet1.tblCustomers); // Updating the DB Table  
}