如何将新行附加到 datagridview 并保留现有行？

Question

我有实验室请求窗口，我可以稍后创建新请求 我需要更新此订单 我创建了更新窗口，我从 datagrid 视图中的数据库中读取了订单详细信息，我需要添加新项目datagridview，但是当我添加新行时出现错误，现有行被删除并添加新行我的代码有什么错误，我正在添加新行。 如何添加新行并保留现有行，还要检查附件 datagridview 图像，然后按 enter 键和 datagridview1 图像，然后按输入其添加新行并删除从数据库中获取的现有行。

private void textAmount_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Enter && textQty.Text != string.Empty && textAmount.Text != string.Empty)
            {
                if (chkcash1.Checked == true)
                {
                    textDiscount.Focus();
                }
                if (chkcash1.Checked == false)
                {
                    for (int i = 0; i < TestsDataGrid.Rows.Count - 1; i++)
                    {
                        if (TestsDataGrid.Rows[i].Cells[0].Value.ToString() == textTestId.Text)
                        {
                            MessageBox.Show("This test added already ", "Duplicate Test", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                            return;
                        }
                    }
                    DataRow r = dt.NewRow();
                    r[0] = textTestId.Text;
                    r[1] = textName.Text;
                    r[2] = textPrice.Text;
                    r[3] = textQty.Text;
                    r[4] = textAmount.Text;
                    r[5] = textTotal.Text;


                    dt.Rows.Add(r);
                    TestsDataGrid.DataSource = dt;
                    textTestId.Clear();
                    textName.Clear();
                    textPrice.Clear();
                    textAmount.Clear();
                    textTotal.Clear();
                    btnSearch.Focus();

                    textOrderTotal.Text = (from DataGridViewRow row in TestsDataGrid.Rows
                                           where row.Cells[4].FormattedValue.ToString() != string.Empty
                                           select Convert.ToDouble(row.Cells[4].FormattedValue)).Sum().ToString();
                }[datagridviewimage][1]

Answer 1

这可能会有所帮助，这里有一个简单的例子：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlServerCe;
using System.Data.OleDb;

namespace Practice
{
    public partial class Form1 : Form
    {
        private DataTable retdt;
        SqlCeDataAdapter da;
        SqlCeCommandBuilder cbuild;
        SqlCeConnection con;
        public Form1()
        {
            InitializeComponent();
            fetchData();
        }
        private void fetchData()
        {
            retdt = new DataTable();
            SqlCeConnection con = null;
            try
            {
                con = new SqlCeConnection(@"Data Source=c:\users\mswami\documents\visual studio 2010\Projects\Practice\Practice\practice.sdf");
                da = new SqlCeDataAdapter();
                da.SelectCommand = new SqlCeCommand("select uid,amount from TestTable", con);
                cbuild = new SqlCeCommandBuilder(da);
                con.Open();
                da.Fill(retdt);
                DGPractice.DataSource = retdt.DefaultView;
                DGPractice.BindingContext = this.BindingContext;
            }
            catch (Exception exce)
            {
                MessageBox.Show(exce.Message);
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (maskedTextBox1.Text.Length > 0)
            {
                if (retdt.Select("amount=" + maskedTextBox1.Text).Length == 0)
                {
                    DataRow drow = retdt.NewRow();
                    // drow[0] left blank as it is primary key column with auto increment value
                    drow[1] = Math.Round(Double.Parse(maskedTextBox1.Text),2);
                    retdt.Rows.Add(drow);

                    //Update changes into database table
                    // First process deletes.  
                    da.Update(retdt.Select(null, null, DataViewRowState.Deleted));

                    // Next process updates.  
                    da.Update(retdt.Select(null, null,
                      DataViewRowState.ModifiedCurrent));

                    // Finally, process inserts.  
                    da.Update(retdt.Select(null, null, DataViewRowState.Added));

                    DGPractice.DataSource = null;
                    DGPractice.DataSource = retdt.DefaultView;
                    DGPractice.BindingContext = this.BindingContext;
                }
                else
                {
                    MessageBox.Show("Duplicate amount");
                }
            }
        }
    }

}

designer.cs 代码（用于 DataGrid 列定义和绑定属性）

 // DGPractice
// 
this.DGPractice.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize;
this.DGPractice.Columns.AddRange(new System.Windows.Forms.DataGridViewColumn[] {
this.UID,
this.amtField});
this.DGPractice.Location = new System.Drawing.Point(2, 63);
this.DGPractice.Name = "DGPractice";
this.DGPractice.RowHeadersVisible = false;
this.DGPractice.Size = new System.Drawing.Size(373, 196);
this.DGPractice.TabIndex = 0;
// 
// UID
// 
this.UID.DataPropertyName = "uid";
this.UID.HeaderText = "UID";
this.UID.Name = "UID";
// 
// amtField
// 
this.amtField.DataPropertyName = "amount";
this.amtField.HeaderText = "Amount";
this.amtField.Name = "amtField";

DataPropertyName 应与选择查询中的字段名称（表字段名称）相同。

Answer 2

谢谢你，Maddy 它解决了我的错误，它没有将数据保留在数据网格视图中，因为我从存储过程中读取并且在获取到数据表后没有保存数据

da.Fill(retdt);
DGPractice.DataSource = retdt.DefaultView;
DGPractice.BindingContext = this.BindingContext;