如何更新组合框，以便在将其添加到数据库后立即显示该记录？ [英] how to update the combobox so it shows that record right after it's added to the db?

问题描述

嗨！

这是我的代码，用于汇总数据库中的数据库。

 Main_Load（ object  sender，EventArgs e）
 {
 bindComboBox（）; 
} 
 
  public   void  bindComboBox（）
 {
 DataTable table =  new  DataTable（）; 
 conn.ConnectionString = connString; 
 conn.Open（）; 
 
 SqlDataAdapter da =  new  SqlDataAdapter（  SELECT * FROM KombiStateTbl，conn）; 
 da.Fill（table）; 
 
 kombiComboBox.DataSource =  new  BindingSource（table， null ）; 
 kombiComboBox.DisplayMember =   NumberPlate; 
 kombiComboBox.ValueMember =   NumberPlate; 
 
 conn.Close（）; 
} 

来自另一种表格的
我可以将另一条记录添加到数据库中。我的问题是：如何更新组合框，以便在将其添加到数据库后立即显示该记录？





这是添加记录的代码：



< pre lang =c＃> private void okButton_Click（ object sender，EventArgs e）
{
int intInsert = 0 ;
字符串 connString =（ @ 数据源= .\SQLEXPRESS; AttachDbFilename = D：\Projects\RentalPlus\RentalPlus\KombiDB.mdf; Integrated Security = True; User Instance = True）;
SqlConnection conn = new SqlConnection（connString）;
SqlCommand cmd = new SqlCommand（）;

cmd.CommandType = CommandType.Text;
cmd.CommandText = INSERT INTO KombiStateTbl（NumberPlate，LicenseExpiryDate，ControlDate，
+ Documentos，FaróisLanternas，EstepeMacacoChaveDeRoda，Triângulo，Extintor，Acendedor，
+ RodasCalota，Retrovisores，Párabrisa，BancosTapetes，Pneus，ParachoqueDianteiro，
+ ParachoqueTraseiro，PortaDianteiraDireitaM，PortaDianteiraEsquerdaP，PortaLateral，
+ LateralEsquerda，LateralEsquerdaTraseira，LateralDireitaTraseira，ParalamaTraseiroDireito，
+ ParalamaTraseiroEsquerdo，Teto，PortaDoPortaMalas ，PortaTraseiraDoMotor，Traseira，
+ Dianteira，FaróisDianteiros，FaroisTraseiros，CurrentPic，CurrentPicPath） VALUES
+ （@ Param1，@ Param2，@ Param3，'OK'， 'OK'，'OK'，'OK'，'OK'，'OK'，'OK'，'OK'，'OK'，'OK'，
+ 确定，确定，确定，确定，确定，确定，确定， OK'，'OK'，'OK'，'OK'，'OK'，'OK'，'OK'，
+ 'OK'，'OK'，'OK'，'OK'，NULL，NULL）;

cmd.Parameters.Add（ @ Param1，SqlDbType.Char ）.Value = noPlateTextBox.Text;
cmd.Parameters.Add（ @ Param2，SqlDbType.Char）.Value = licenseDateTimePicker.Text;
cmd.Parameters.Add（ @ Param3，SqlDbType.Char）.Value = controlDateTimePicker.Text;

cmd.Connection = conn;

conn.Open（）;
intInsert = cmd.ExecuteNonQuery（）;
conn.Close（）;

if （intInsert！= 0 ）
{
MessageBox.Show（ 数据插入成功， 成功，MessageBoxButtons.OK，
MessageBoxIcon.Information）;
noPlateTextBox.Text = ;
okButton.Enabled = false ;

}
else
{
MessageBox.Show（ 数据插入失败， 错误，MessageBoxButtons.RetryCancel，
MessageBoxIcon.Error）;
}
}

请帮忙。

解决方案

你需要做一个重新加载以重新收集更新的内容，然后在添加该内容后更新组合框的数据源。



这在if语句中应修复：

  if （intInsert！=  0 ）
 {
 MessageBox.Show（ 数据插入成功， 成功，MessageBoxButtons.OK，
 MessageBoxIcon.Information）; 
 noPlateTextBox.Text =  ; 
 okButton.Enabled =  false ; 
 
 bindComboBox（）;  //  <<  - 更新后重新收集组合框的内容。 
 
 } 

对不起，我唯一一个调用上面绑定行的错误。



只需添加在ok_Button.Enabled = false之后，在ok按钮内调用if条件;



所以你的okButton_Click看起来像这样：

 private void okButton_Click（object sender，EventArgs e）
 {
 int intInsert = 0; 
 String connString =（@Data Source = .\SQLEXPRESS; AttachDbFilename = D：\Projects\RentalPlus\RentalPlus\KombiDB.mdf; Integrated Security = True; User Instance = True）; 
 SqlConnection conn = new SqlConnection（connString）; 
 SqlCommand cmd = new SqlCommand（）; 
 
 cmd.CommandType = CommandType.Text; 
 cmd.CommandText =INSERT INTO KombiStateTbl（NumberPlate，LicenseExpiryDate，ControlDate，
 +Documentos，FaróisLanternas，EstepeMacacoChaveDeRoda，Triângulo，Extintor，Acendedor，
 +RodasCalota，Retrovisores，Párabrisa ，BancosTapetes，Pneus，ParachoqueDianteiro，
 +ParachoqueTraseiro，PortaDianteiraDireitaM，PortaDianteiraEsquerdaP，PortaLateral，
 +LateralEsquerda，LateralEsquerdaTraseira，LateralDireitaTraseira，ParalamaTraseiroDireito，
 +ParalamaTraseiroEsquerdo，Teto，PortaDoPortaMalas， PortaTraseiraDoMotor，Traseira，
 +Dianteira，FaróisDianteiros，FaroisTraseiros，CurrentPic，CurrentPicPath）价值
 +（@ Param1，@ Param2，@ Param3，''OK''，''OK'' ，''确定'，''确定''，''确定''，''确定''，''确定''，''确定''，''确定''，''确定''， 
 +''确定''，' OK''，''OK''，''OK''，''OK''，''OK''，''OK''，''OK''，''OK''，''OK' '，''确定''，''确定''，''确定''，''确定''，
 +''确定''，''确定''，''确定''' ，''确定''，NULL，NULL）; 
 
 cmd.Parameters.Add（@ Param1，SqlDbType.Char）.Value = noPlateTextBox.Text; 
 cmd.Parameters.Add（@ Param2，SqlDbType.Char）.Value = licenseDateTimePicker.Text; 
 cmd.Parameters.Add（@ Param3，SqlDbType.Char）.Value = controlDateTimePicker.Text; 
 
 cmd.Connection = conn; 
 
 conn.Open（）; 
 intInsert = cmd.ExecuteNonQuery（）; 
 conn.Close（）; 
 
 if（intInsert！= 0）
 {
 MessageBox.Show（数据插入成功，成功，MessageBoxButtons.OK，
 MessageBoxIcon。信息）; 
 noPlateTextBox.Text =; 
 okButton.Enabled = false; 
 
 Main_Load.bindComboBox（）; //这里是需要的电话<<<<< br mode =hold/> 
} 
 else 
 {
 MessageBox.Show（数据插入失败，错误，MessageBoxButtons.RetryCancel，
 MessageBoxIcon.Error）; 
} 
} 

好的，我明白了。我发现它在互联网上的某个地方。它完成了这项工作！

主要m =（主要）Application.OpenForms [  Main]; 
 m.bindComboBox（）; 

wolfcoder75，谢谢你的输入。

Hi!
this is my code to polulate a combobox with data from the database.

Main_Load(object sender, EventArgs e)
        {
            bindComboBox();
        }

        public void bindComboBox()
        {
            DataTable table = new DataTable();
            conn.ConnectionString = connString;
            conn.Open();

            SqlDataAdapter da = new SqlDataAdapter("SELECT * FROM KombiStateTbl", conn);
            da.Fill(table);

            kombiComboBox.DataSource = new BindingSource(table, null);
            kombiComboBox.DisplayMember = "NumberPlate";
            kombiComboBox.ValueMember = "NumberPlate";

            conn.Close();
        }

from another form I can add another record to the database. my question is: how to update the combobox so it shows that record right after it''s added to the db?


this is the code to add a record:

private void okButton_Click(object sender, EventArgs e)
        {
            int intInsert = 0;
            String connString = (@"Data Source=.\SQLEXPRESS;AttachDbFilename=D:\Projects\RentalPlus\RentalPlus\KombiDB.mdf;Integrated Security=True;User Instance=True");
            SqlConnection conn = new SqlConnection(connString);
            SqlCommand cmd = new SqlCommand();

            cmd.CommandType = CommandType.Text;
            cmd.CommandText = "INSERT INTO KombiStateTbl (NumberPlate, LicenseExpiryDate, ControlDate, "
            + "Documentos, FaróisLanternas, EstepeMacacoChaveDeRoda, Triângulo, Extintor, Acendedor, "
            + "RodasCalota, Retrovisores, Párabrisa, BancosTapetes, Pneus, ParachoqueDianteiro, "
            + "ParachoqueTraseiro, PortaDianteiraDireitaM, PortaDianteiraEsquerdaP, PortaLateral, "
            + "LateralEsquerda, LateralEsquerdaTraseira, LateralDireitaTraseira, ParalamaTraseiroDireito, "
            + "ParalamaTraseiroEsquerdo, Teto, PortaDoPortaMalas, PortaTraseiraDoMotor, Traseira, "
            + "Dianteira, FaróisDianteiros, FaroisTraseiros, CurrentPic, CurrentPicPath) VALUES "
            + "(@Param1,@Param2,@Param3, 'OK', 'OK', 'OK', 'OK', 'OK', 'OK', 'OK', 'OK', 'OK', 'OK', "
            + "'OK', 'OK', 'OK', 'OK', 'OK', 'OK', 'OK', 'OK', 'OK', 'OK', 'OK', 'OK', 'OK', 'OK', "
            + "'OK', 'OK', 'OK', 'OK', NULL, NULL)";

            cmd.Parameters.Add("@Param1", SqlDbType.Char).Value = noPlateTextBox.Text;
            cmd.Parameters.Add("@Param2", SqlDbType.Char).Value = licenseDateTimePicker.Text;
            cmd.Parameters.Add("@Param3", SqlDbType.Char).Value = controlDateTimePicker.Text;
            
            cmd.Connection = conn;

            conn.Open();
            intInsert = cmd.ExecuteNonQuery();
            conn.Close();

            if (intInsert != 0)
            {
                MessageBox.Show("The data insertion is successful", "Success", MessageBoxButtons.OK,
                    MessageBoxIcon.Information);
                noPlateTextBox.Text = "";
                okButton.Enabled = false;                
               
            }
            else
            {
                MessageBox.Show("The data insertion is failed", "Error", MessageBoxButtons.RetryCancel,
                    MessageBoxIcon.Error);
            }            
        }

Please help.

解决方案

You need to do a reload to recollect the updated content and then update the datasource of the combo box after you added that content.

this in your if statement should fix that:

if (intInsert != 0)
{
    MessageBox.Show("The data insertion is successful", "Success", MessageBoxButtons.OK,
        MessageBoxIcon.Information);
    noPlateTextBox.Text = "";
    okButton.Enabled = false;
    
    bindComboBox();        //<<- Recollect content for combobox after update.

}

sorry, my fault on the only calling the bind line above.

Just add the call to your if condition inside your ok button click after ok_Button.Enabled = false;

So your okButton_Click would look like this:

private void okButton_Click(object sender, EventArgs e)
        {
            int intInsert = 0;
            String connString = (@"Data Source=.\SQLEXPRESS;AttachDbFilename=D:\Projects\RentalPlus\RentalPlus\KombiDB.mdf;Integrated Security=True;User Instance=True");
            SqlConnection conn = new SqlConnection(connString);
            SqlCommand cmd = new SqlCommand();
 
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = "INSERT INTO KombiStateTbl (NumberPlate, LicenseExpiryDate, ControlDate, "
            + "Documentos, FaróisLanternas, EstepeMacacoChaveDeRoda, Triângulo, Extintor, Acendedor, "
            + "RodasCalota, Retrovisores, Párabrisa, BancosTapetes, Pneus, ParachoqueDianteiro, "
            + "ParachoqueTraseiro, PortaDianteiraDireitaM, PortaDianteiraEsquerdaP, PortaLateral, "
            + "LateralEsquerda, LateralEsquerdaTraseira, LateralDireitaTraseira, ParalamaTraseiroDireito, "
            + "ParalamaTraseiroEsquerdo, Teto, PortaDoPortaMalas, PortaTraseiraDoMotor, Traseira, "
            + "Dianteira, FaróisDianteiros, FaroisTraseiros, CurrentPic, CurrentPicPath) VALUES "
            + "(@Param1,@Param2,@Param3, ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', "
            + "''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', ''OK'', "
            + "''OK'', ''OK'', ''OK'', ''OK'', NULL, NULL)";
 
            cmd.Parameters.Add("@Param1", SqlDbType.Char).Value = noPlateTextBox.Text;
            cmd.Parameters.Add("@Param2", SqlDbType.Char).Value = licenseDateTimePicker.Text;
            cmd.Parameters.Add("@Param3", SqlDbType.Char).Value = controlDateTimePicker.Text;
            
            cmd.Connection = conn;
 
            conn.Open();
            intInsert = cmd.ExecuteNonQuery();
            conn.Close();
 
            if (intInsert != 0)
            {
                MessageBox.Show("The data insertion is successful", "Success", MessageBoxButtons.OK,
                    MessageBoxIcon.Information);
                noPlateTextBox.Text = "";
                okButton.Enabled = false;  
              
                Main_Load.bindComboBox();    //here is the call needed   <<<<br mode="hold" />             
            }
            else
            {
                MessageBox.Show("The data insertion is failed", "Error", MessageBoxButtons.RetryCancel,
                    MessageBoxIcon.Error);
            }            
        }

Ok, i got it. i found it somewhere on the internet. it did the job!

Main m = (Main)Application.OpenForms["Main"];
                m.bindComboBox();

wolfcoder75, thank you for yr input.

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