从数据网格视图和数据库中删除选定的行

Posted 2023-04-11

【中文标题】从数据网格视图和数据库中删除选定的行

【英文标题】：Delete selected rows from data grid view and database

【发布时间】：2021-03-27 19:25:02

【问题描述】：

在我的 WinForms 应用程序中，我需要同时并保存数据库。

我有这个下面的代码，现在它只从 datagridview 中删除，而不是从数据库中删除，请指导我哪里错了。

private void button1_Click(object sender, EventArgs e)

    try
    
        String msg = "Confirm Delete?";
        String caption = "Delete Record";
        MessageBoxButtons buttons = MessageBoxButtons.YesNo;
        MessageBoxIcon ico = MessageBoxIcon.Question;
        DialogResult result;
        result = MessageBox.Show(this, msg, caption, buttons, ico);
        if (result == DialogResult.Yes)
        
            foreach (DataGridViewRow item in this.iP_SpoolsDataGridView.SelectedRows)
            
                using (SqlConnection con = new SqlConnection(cs))
                
                    SqlCommand cmd = con.CreateCommand();
                    int id = Convert.ToInt32(iP_SpoolsDataGridView.SelectedRows[0].Cells[0].Value);
                    cmd.CommandText = "Delete from Lot_Numbers where ID='" + id + "'";

                    iP_SpoolsDataGridView.Rows.RemoveAt(this.iP_SpoolsDataGridView.SelectedRows[0].Index);
                    con.Open();
                    cmd.ExecuteNonQuery();

                

            
        
        else
        
            return;
        
    
    catch (Exception ex)
    
        MessageBox.Show("Deleting Failed:" + ex.Message.ToString(), "Delete",
            MessageBoxButtons.OK, MessageBoxIcon.Error);
    

【问题讨论】：

它抛出异常？如果是，什么样的例外？

【参考方案1】：

试试这个：

private void button1_Click(object sender, EventArgs e)

    try
    
        String msg = "Confirm Delete?";
        String caption = "Delete Record";
        MessageBoxButtons buttons = MessageBoxButtons.YesNo;
        MessageBoxIcon ico = MessageBoxIcon.Question;
        DialogResult result;
        result = MessageBox.Show(this, msg, caption, buttons, ico);
        if (result == DialogResult.Yes)
        
            int id = 0;
            foreach (DataGridViewRow item in this.iP_SpoolsDataGridView.SelectedRows)
            
                id = Convert.ToInt32(item.Cells[0].Value.ToString());
                if (Database_Remove_LotNumberById(id))
                
                    iP_SpoolsDataGridView.Rows.RemoveAt(item.Index);
                
            
        
        else
        
            return;
        
    
    catch (Exception ex)
    
        MessageBox.Show("Deleting Failed:" + ex.Message.ToString(), "Delete",
            MessageBoxButtons.OK, MessageBoxIcon.Error);
    



//The code become clean if you separate the Database Operations
private bool Database_Remove_LotNumberById(int IdLotNumber)

    bool IsRemovedFromDatabase = false;
    try
    
        using (SqlConnection con = new SqlConnection(cs))
        
            SqlCommand cmd = con.CreateCommand();
            cmd.CommandText = "Delete from Lot_Numbers where ID= @ID";
            cmd.Parameters.AddWithValue("@ID", IdLotNumber);
            con.Open();
            cmd.ExecuteNonQuery();
            IsRemovedFromDatabase = true;
        
    
    catch (SqlException ex)
    
        // Handle the SQL Exception as you wish
        MessageBox.Show("Deleting Failed:" + ex.Message.ToString(), "Delete", MessageBoxButtons.OK, MessageBoxIcon.Error);
        //or throw 
    
    return IsRemovedFromDatabase;

【讨论】：

为了获得高质量的答案，除了提供代码之外，请说明您所做的更改。