如何将值作为空的gridview的datetime列，它列为空 [英] How can I get the value as empty of a datetime column of the gridview , it column is empty

问题描述

嗨

当我检查 的价值时gridview列的空日期时间单元格，它始终显示'01 -01-0001'，如何将gridview的空日期时间列的值设置为空而不是'01 -01-0001'请在c＃中提供帮助。在给定的示例中，
如果MotDate为空，则ls值也应为空或为null。 
$
var ls = Convert.ToDateTime（dt1.Rows [0] .Field< ; DateTime>（" MotDate"））;
$
var ls1 = Convert.ToDateTime（dt1.Rows [0] .Field< DateTime>（" TaxDate"））;

 private void grvListVehicle_CellClick（object sender，DataGridViewCellEventArgs e）
 {
 if（e.ColumnIndex == 0）
 {
 DataTable dt = new DataTable（）; 
 for（int j = 0; j< grvListVehicle.Columns.Count; j ++）
 {
 if（j> = 1）
 dt.Columns.Add（grvListVehicle .Columns [j] .Name，grvListVehicle.Columns [j] .CellType）; 
} 
 DataRow row = dt.NewRow（）; 
 dt.Rows.Add（row）; 
 var dt1 =（（DataTable）grvListVehicle.DataSource）.Clone（）; 
 var currentRowData = grvListVehicle.CurrentRow.Cells.OfType< DataGridViewTextBoxCell>（）。选择（cell => cell.Value）.ToArray（）; 
 dt1.Rows.Add（currentRowData）; 
 var _regno = dt1.Rows [0] .Field< string>（" VehicleType"）; 
 var ls = Convert.ToDateTime（dt1.Rows [0] .Field< DateTime>（" MotDate"））; 
 var ls1 = Convert.ToDateTime（dt1.Rows [0] .Field< DateTime>（" TaxDate"））; 
 
 
 frmVehicle frm = new frmVehicle（dt1）; 
 this.Close（）; 
 frm.Show（）; 
} 
} 

Pol

---

polachan

解决方案

您好，

如果我们在临床上看一下，您就不应该触摸DataGridView来获取值，例如

 DataTable dtSource = new DataTable（）; 
 dtSource.Columns.Add（new DataColumn（）{ColumnName =" Event"，DataType = typeof（string）}）; 
 dtSource.Columns.Add（new DataColumn（）{ColumnName =" d1"，DataType = typeof（DateTime）}）; 
 
 dtSource.Rows.Add（new object [] {" Jog"，null}）; 
 dtSource.Rows.Add（new object [] {" Run"，DateTime.Now}）; 
 
 dataGridView1.DataSource = dtSource; 
 
 var dMinDate = DateTime.MinValue; 
 
 dtSource.Rows.Add（new object [] {" walk"，dMinDate}）; 
 dtSource.Rows.Add（new object [] {" rest"，DateTime.Now.AddDays（2）}）; 
 
 
 DataTable dtTarget = dtSource.Clone（）; 
 dataGridView2.DataSource = dtTarget; 
 
 foreach（dtSource.Rows中的DataRow行）
 {
 dtTarget.ImportRow（row）; 
} 

如果您需要获取单行，请检查空日期，我们可以使用BindingSource，如下所示，从而不会触及DataGridView元素。 / p>

 public partial class Form1：Form 
 {
 public Form1（）
 {
 InitializeComponent（） ; 
} 
 
 private void button1_Click（object sender，EventArgs e）
 {
 if（bsSource.Current！= null）
 {
 var row =（（DataRowView）bsSource.Current）.Row; 
 
 
 var test = row [" d1"]。GetType（）; 
 if（row [" d1"]！= DBNull.Value）
 {
 Console.WriteLine（row.Field< DateTime>（" d1"））; 
} 
其他
 {
 //我们有一个空日期
} 
 
} 
} 
 BindingSource bsSource = new BindingSource（）; 
 private void Form1_Load（object sender，EventArgs e）
 {
 
 DataTable dtSource = new DataTable（）; 
 dtSource.Columns.Add（new DataColumn（）{ColumnName =" Event"，DataType = typeof（string）}）; 
 dtSource.Columns.Add（new DataColumn（）{ColumnName =" d1"，DataType = typeof（DateTime）}）; 
 
 dtSource.Rows.Add（new object [] {" Jog"，null}）; 
 dtSource.Rows.Add（new object [] {" Run"，DateTime.Now}）; 
 
 
 var dMinDate = DateTime.MinValue; 
 
 dtSource.Rows.Add（new object [] {" walk"，dMinDate}）; 
 dtSource.Rows.Add（new object [] {" rest"，DateTime.Now.AddDays（2）}）; 
 
 bsSource.DataSource = dtSource; 
 dataGridView1.DataSource = bsSource; 
} 
} 

Hi
When I am checking the value of  empty datetime cell of gridview column , it shows always '01-01-0001' , How can I get the value of empty datetime column of the gridview as empty rather than '01-01-0001' Please can you help in c#. In the given example, if the MotDate is empty , the ls value should also be empty or null. 
var ls = Convert.ToDateTime(dt1.Rows[0].Field<DateTime>("MotDate"));
var ls1 = Convert.ToDateTime(dt1.Rows[0].Field<DateTime>("TaxDate"));

private void grvListVehicle_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            if (e.ColumnIndex == 0)
            {
                DataTable dt = new DataTable();
                for (int j = 0; j < grvListVehicle.Columns.Count; j++)
                {
                    if (j >= 1)
                        dt.Columns.Add(grvListVehicle.Columns[j].Name, grvListVehicle.Columns[j].CellType);
                }
                DataRow row = dt.NewRow();
                dt.Rows.Add(row);
                var dt1 = ((DataTable)grvListVehicle.DataSource).Clone();
                var currentRowData = grvListVehicle.CurrentRow.Cells.OfType<DataGridViewTextBoxCell>().Select(cell => cell.Value).ToArray();
                dt1.Rows.Add(currentRowData);
                var _regno = dt1.Rows[0].Field<string>("VehicleType");
                var ls = Convert.ToDateTime(dt1.Rows[0].Field<DateTime>("MotDate"));
                var ls1 = Convert.ToDateTime(dt1.Rows[0].Field<DateTime>("TaxDate"));


                frmVehicle frm = new frmVehicle(dt1);
                this.Close();
                frm.Show();
            }
        }

Pol

---

polachan

解决方案

Hello,

If we look at this clinically you should never have to touch the DataGridView to get values e.g.

            DataTable dtSource = new DataTable();
            dtSource.Columns.Add(new DataColumn() { ColumnName = "Event", DataType = typeof(string) });
            dtSource.Columns.Add(new DataColumn() { ColumnName = "d1", DataType = typeof(DateTime) });

            dtSource.Rows.Add(new object[] {"Jog",null});
            dtSource.Rows.Add(new object[] {"Run", DateTime.Now });

            dataGridView1.DataSource = dtSource;

            var dMinDate = DateTime.MinValue;

            dtSource.Rows.Add(new object[] {"walk", dMinDate });
            dtSource.Rows.Add(new object[] { "rest", DateTime.Now.AddDays(2) });


            DataTable dtTarget = dtSource.Clone();
            dataGridView2.DataSource = dtTarget;

            foreach (DataRow row in dtSource.Rows)
            {
                dtTarget.ImportRow(row);
            }

If you need to get at a single row, check for a null date we can use a BindingSource as shown below thus never touching the DataGridView elements.

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        if (bsSource.Current != null)
        {
            var row = ((DataRowView)bsSource.Current).Row;
            
            
                var test = row["d1"].GetType();
                if (row["d1"] != DBNull.Value)
                {
                    Console.WriteLine(row.Field<DateTime>("d1"));
                }
                else
                {
                    // we have a null date
                }                   
            
        }
    }
    BindingSource bsSource = new BindingSource();
    private void Form1_Load(object sender, EventArgs e)
    {

        DataTable dtSource = new DataTable();
        dtSource.Columns.Add(new DataColumn() { ColumnName = "Event", DataType = typeof(string) });
        dtSource.Columns.Add(new DataColumn() { ColumnName = "d1", DataType = typeof(DateTime) });

        dtSource.Rows.Add(new object[] {"Jog",null});
        dtSource.Rows.Add(new object[] {"Run", DateTime.Now });


        var dMinDate = DateTime.MinValue;

        dtSource.Rows.Add(new object[] {"walk", dMinDate });
        dtSource.Rows.Add(new object[] { "rest", DateTime.Now.AddDays(2) });

        bsSource.DataSource = dtSource;
        dataGridView1.DataSource = bsSource;
    }
}

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