如何在按钮单击事件中向数据表添加行？

Aung Kaung Hein 发表于 Dev

昂江轩

在Windows Forms中，我想通过从其他控件中获取值，将按钮单击事件中的行逐行添加到DataGridView中。在这种情况下，我使用的是DataTable，它已绑定到DataGridView。

我正在使用以下代码，并且在首次插入数据时工作正常。但是我的问题是，当我第二次单击该按钮时，第一行被第二行数据覆盖。

private void btnAddToGrid_Click(object sender, EventArgs e)
{
        LoadDataGridView();
}

private void LoadDataGridView()
{
        dgvAdjustment.DataSource = GetAdjustmentTable();
}

private DataTable GetAdjustmentTable()
{
        DataTable adjustmentTable = new DataTable();

        DataColumn dataColumn;
        dataColumn = new DataColumn("SourceOutletID", typeof(int));
        adjustmentTable.Columns.Add(dataColumn);
        dataColumn = new DataColumn("DestinationOutletID", typeof(int));
        adjustmentTable.Columns.Add(dataColumn);
        dataColumn = new DataColumn("TransactionDate", typeof(DateTime));
        adjustmentTable.Columns.Add(dataColumn);
        dataColumn = new DataColumn("MaterialName", typeof(string));
        adjustmentTable.Columns.Add(dataColumn);
        dataColumn = new DataColumn("AdjustmentType", typeof(int));
        adjustmentTable.Columns.Add(dataColumn);
        dataColumn = new DataColumn("CurrentBalance", typeof(decimal));
        adjustmentTable.Columns.Add(dataColumn);
        dataColumn = new DataColumn("AdjustmentQty", typeof(decimal));
        adjustmentTable.Columns.Add(dataColumn);
        dataColumn = new DataColumn("NewBalance", typeof(decimal));
        adjustmentTable.Columns.Add(dataColumn);

        DataRow dataRow = adjustmentTable.NewRow();
        dataRow[0] = cmbSourceOutlet.SelectedValue;
        dataRow[1] = cmbDestinationOutlet.SelectedValue;
        dataRow[2] = TransDateTimePicker.Value;
        dataRow[3] = cmbMaterialName.SelectedValue;
        dataRow[4] = cmbAdjustmentType.SelectedValue;
        dataRow[5] = Convert.ToDecimal(lblCurBalVal.Text);
        dataRow[6] = Convert.ToDecimal(lblAdjVal.Text);
        dataRow[7] = Convert.ToDecimal(lblNewQtyVal.Text);

        int insertPosition = adjustmentTable.Rows.Count;
        adjustmentTable.Rows.InsertAt(dataRow, insertPosition);

        return adjustmentTable;
}

在ASP .NET应用程序中，我使用会话状态通过以下代码检查DataTable是否为空：

protected void Button1_Click(object sender, EventArgs e)
{
  try
  {
     //Check if previous session is exist
     if (Session["MyTable"] == null)
     {
         dtMyTable = new DataTable("MyTable");
         dtMyTable.Columns.Add("Id", typeof(int));
         dtMyTable.Columns.Add("LName", typeof(string));

     }
     else
     {
         //If yes then get it from current session
         dtMyTable = (DataTable)Session["MyTable"];
     }

     //Add new row every time
     DataRow dt_row;
     dt_row = dtMyTable.NewRow();
     dt_row["Id"] = TextBox1.Text;
     dt_row["LName"] = TextBox2.Text;
     dtMyTable.Rows.Add(dt_row);

     //Update session table
     Session["MyTable"] = dtMyTable;
  }
  catch (Exception ex)
  {

     Response.Write(ex.Message);
  }
}

我该怎么办，如何进行更改以获取Windows窗体中的正确解决方案？任何帮助都感激不尽！

大卫·阿尔诺

在中GetAdjustmentTable，您adjustmentTable每次都在重新创建。因此，新行将覆盖现有行。

您需要修改adjustmentTable仅创建一次的代码，随后的调用会向其中添加行。一种方法是将其设置为私有字段，并检查其是否为空，如果为空，则创建它：

private DataTable _adjustmentTable;

private DataTable GetAdjustmentTable()
{
    if (adjustmentTable == null)
    {
        adjustmentTable = new DataTable();
    }
    ....

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