Windows窗体-从上次访问表值开始自动递增窗体编号
本文关键字：窗体 编号 开始 访问表 Windows | 更新日期: 2023-09-27 18:26:23
我有一个windows窗体（在VisualStudio-10中），它可以将条目加载/保存到数据库中，导航现有条目并在窗体中编辑它们。我想做的是，每当创建新条目时，让窗体编号（每个条目的4位主键）从Access DB表中的最后一个条目开始递增1。
有没有办法调用最后一个条目的索引，将其递增1，然后将该数字打印到表单编号文本框中？到目前为止，我还没能在搜索中找到很多有用的信息，所以如果你能给我指明正确的方向或另一个问题，我将不胜感激，谢谢。
这是数据库的更新功能/连接。数据库名称为servicereq1，表名称为
servicereq。我希望在中显示更新密钥的文本框是serviceRequestNumberTextBox。再次感谢您的帮助。
private void updateButton_Click_1(object sender, EventArgs e)
{
{
OleDbConnection conn = new OleDbConnection();
AppDomain.CurrentDomain.SetData("DataDirectory", @"''prod'ServiceRequests");
conn.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|'servicereq1.mdb";
OleDbCommand cmd = new OleDbCommand("UPDATE servicereq SET ServiceRequestNumber = @servreq, DateLogged = @datelogged, LoggedBy = @loggedby, [Problem In Environment] = @problemfoundin, Function = @function, [Other Impacts] = @summary, Account = @earningsaccount, [From] = @from, [To] = @to, Status = @status, Description = @description, Fixer = @fixer, [Time Estimate] = @timeestimate, [Actual Start] = @actualstart, [Actual Finish] = @actualfinish, [Actual Time] = @actualtime, [Programs/Forms] = @programsforms, Comments = @comments, [Retest Date] = @requestdate, Tester = @tester, [Code In Environment] = @codein WHERE (ServiceRequestNumber = @servreq)");
cmd.Connection = conn;
conn.Open();
if (conn.State == ConnectionState.Open)
{
cmd.Parameters.AddWithValue("@servreq", serviceRequestNumberTextBox.Text);
cmd.Parameters.AddWithValue("@datelogged", dateLoggedTextBox.Text);
cmd.Parameters.AddWithValue("@loggedby", loggedByComboBox.Text);
cmd.Parameters.AddWithValue("@problemfoundin", problem_In_EnvironmentComboBox.Text);
cmd.Parameters.AddWithValue("@function", functionTextBox.Text);
cmd.Parameters.AddWithValue("@summary", other_ImpactsTextBox.Text);
cmd.Parameters.AddWithValue("@earningsaccount", accountTextBox.Text);
cmd.Parameters.AddWithValue("@from", fromTextBox.Text);
cmd.Parameters.AddWithValue("@to", toTextBox.Text);
cmd.Parameters.AddWithValue("@status", statusComboBox.Text);
cmd.Parameters.AddWithValue("@description", descriptionTextBox.Text);
cmd.Parameters.AddWithValue("@fixer", fixerComboBox.Text);
cmd.Parameters.AddWithValue("@timeestimate", time_EstimateTextBox.Text);
cmd.Parameters.AddWithValue("@actualstart", actual_StartTextBox.Text);
cmd.Parameters.AddWithValue("@actualfinish", actual_FinishTextBox.Text);
cmd.Parameters.AddWithValue("@actualtime", actual_TimeTextBox.Text);
cmd.Parameters.AddWithValue("@programsforms", programs_FormsTextBox.Text);
cmd.Parameters.AddWithValue("@comments", commentsTextBox.Text);
cmd.Parameters.AddWithValue("@requestdate", retest_DateTextBox.Text);
cmd.Parameters.AddWithValue("@tester", testerComboBox.Text);
cmd.Parameters.AddWithValue("@codein", code_In_EnvironmentComboBox.Text);
cmd.Parameters.AddWithValue("@servreq", serviceRequestNumberTextBox.Text);
try
{
cmd.ExecuteNonQuery();
MessageBox.Show("Form Updated Successfully");
conn.Close();
}
catch (OleDbException ex)
{
MessageBox.Show(ex.Message);
conn.Close();
}
}
else
{
MessageBox.Show("Connection Failed");
}
}
}
这是保存新记录的功能。
private void updateButton_Click(object sender, EventArgs e)
{
{
OleDbConnection conn = new OleDbConnection();
AppDomain.CurrentDomain.SetData("DataDirectory", @"''prod'ServiceRequests");
conn.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|'servicereq1.mdb";
String servreq = serviceRequestNumberTextBox.Text;
String datelogged = dateLoggedTextBox.Text;
String loggedby = loggedByComboBox.Text;
String problemfoundin = problem_In_EnvironmentComboBox.Text;
String function = functionTextBox.Text;
String summary = other_ImpactsTextBox.Text;
String earningsaccount = accountTextBox.Text;
String from = fromTextBox.Text;
String to = toTextBox.Text;
String status = statusComboBox.Text;
String description = descriptionTextBox.Text;
String fixer = fixerComboBox.Text;
String codein = code_In_EnvironmentComboBox.Text;
String programsforms = programs_FormsTextBox.Text;
String timeestimate = time_EstimateTextBox.Text;
String actualstart = actual_StartTextBox.Text;
String actualfinish = actual_FinishTextBox.Text;
String actualtime = actual_TimeTextBox.Text;
String retestdate = retest_DateTextBox.Text;
String tester = testerComboBox.Text;
String comments = commentsTextBox.Text;
OleDbCommand cmd = new OleDbCommand("INSERT into servicereq ([ServiceRequestNumber], DateLogged, LoggedBy, [Problem In Environment], Function, [Other Impacts], Account, [From], [To], Status, Description, Fixer, [Code In Environment], [Programs/Forms], [Time Estimate], [Actual Start], [Actual Finish], [Actual Time], [Retest Date], Tester, Comments) Values(@servreq, @datelogged, @loggedby, @problemfoundin, @function, @summary, @earningsaccount, @from, @to, @status, @description, @fixer, @codein, @programsforms, @timeestimate, @actualstart, @actualfinish, @actualtime, @requestdate, @tester, @comments)");
cmd.Connection = conn;
conn.Open();
if (conn.State == ConnectionState.Open)
{
cmd.Parameters.Add("@servreq", OleDbType.VarChar).Value = servreq;
cmd.Parameters.Add("@datelogged", OleDbType.VarChar).Value = datelogged;
cmd.Parameters.Add("@loggedby", OleDbType.VarChar).Value = loggedby;
cmd.Parameters.Add("@problemfoundin", OleDbType.VarChar).Value = problemfoundin;
cmd.Parameters.Add("@function", OleDbType.VarChar).Value = function;
cmd.Parameters.Add("@summary", OleDbType.VarChar).Value = summary;
cmd.Parameters.Add("@earningsaccount", OleDbType.VarChar).Value = earningsaccount;
cmd.Parameters.Add("@from", OleDbType.VarChar).Value = from;
cmd.Parameters.Add("@to", OleDbType.VarChar).Value = to;
cmd.Parameters.Add("@status", OleDbType.VarChar).Value = status;
cmd.Parameters.Add("@description", OleDbType.VarChar).Value = description;
cmd.Parameters.Add("@fixer", OleDbType.VarChar).Value = fixer;
cmd.Parameters.Add("@codein", OleDbType.VarChar).Value = codein;
cmd.Parameters.Add("@programsforms", OleDbType.VarChar).Value = programsforms;
cmd.Parameters.Add("@timeestimate", OleDbType.VarChar).Value = timeestimate;
cmd.Parameters.Add("@actualstart", OleDbType.VarChar).Value = actualstart;
cmd.Parameters.Add("@actualfinish", OleDbType.VarChar).Value = actualfinish;
cmd.Parameters.Add("@actualtime", OleDbType.VarChar).Value = actualtime;
cmd.Parameters.Add("@requestdate", OleDbType.VarChar).Value = retestdate;
cmd.Parameters.Add("@tester", OleDbType.VarChar).Value = tester;
cmd.Parameters.Add("@comments", OleDbType.VarChar).Value = comments;
try
{
cmd.ExecuteNonQuery();
MessageBox.Show("Form Submitted Successfully");
servicereqBindingSource.ResetBindings(true);
conn.Close();
}
catch (OleDbException ex)
{
MessageBox.Show(ex.Message);
conn.Close();
}
}
else
{
MessageBox.Show("Connection Failed");
}
this.servicereqTableAdapter1.Load(servicereq1DataSet2.servicereq, serviceRequestNumberTextBox.Text);
}
}
在这样的多用户场景中，正确的方法是将ServiceRequestNumber字段更改为AUTONUMBER字段。通过这种方式，数据库引擎计算出新的号码，你就不会冒险将同一号码分配给在同一数据库中工作但来自两台不同电脑的不同用户
当然，您不需要在INSERT查询中传递该字段的任何内容，所以从INSERT查询文本中删除ServerRequestNumber及其参数占位符。
如果你想知道分配给你的记录的AUTONUMBER是什么，你可以写这个sql
using(OleDbConnection conn = new OleDbConnection(......))
using(OleDbCommand cmd = new OleDbCommand("SELECT @@IDENTITY", conn))
{
conn.Open();
int newServiceRequestNumber = Convert.ToInt32(cmd.ExecuteScalar());
....
}
请注意，您应该将连接和其他一次性对象保留在using块中，以确保它们已被处理并关闭
正如Steve在评论中所说，最简单的方法是将colunm设置为数据库中的自动编号，并在添加新条目的表单中删除id的文本框。在INSERT命令中，不要为id指定任何值，数据库将自动为该新条目生成一个新编号（最后一个id+1）。