如何使用foreach循环读取数据表 [英] How do I use a foreach loop to read a datatable

问题描述

我想在搜索数据时使用foreach循环进行迭代以遍历数据表。下面是搜索按钮的代码，其中输入地址并按下搜索按钮，应用程序必须从googlemaps返回GPS坐标，街道地址，省等，但它不会返回任何内容。请协助。代码如下。

I want to iterate using a foreach loop to loop through a datatable when I search for data. Below is code for a search button where an address is entered and a search button is pressed and the application must return GPS coordinates, street address, province etc from googlemaps but it does not return anything. Please assist. Code below.

private void btnSearch_Click(object sender, EventArgs e)
{
   if (String.IsNullOrEmpty(txtSearchText.Text) || String.IsNullOrWhiteSpace(txtSearchText.Text))
   {
      MessageBox.Show("Enter a Search value", "You have not entered any address to search", MessageBoxButtons.OK, MessageBoxIcon.Information);
      return;
   }
   
   AddressServiceData _AddressServiceData = new AddressServiceData();
   try
   {
      DataTable DV = new DataTable();
      string Address = string.Empty;
      
      foreach (DataRow row in DV.Rows)
      {
         Address = row["Address1"].ToString();
         DV = _AddressServiceData.GetGoogleSearch("", Address=txtSearchText.Text + " South Africa", "", "");
      }
      gridView1.Columns.Clear();
      grdaddress.DataSource = DV;
      gridView1.BestFitColumns();
      AddressClassNew.SearchAttempt = true;
   }
   catch
   {
      AddressClassNew.SearchAttempt = true;
      MessageBox.Show("Could not find Address");
      return;
   }
}

推荐答案

逐步完成逻辑。如果要迭代数据表的行，那么在尝试循环遍历行之前需要将行放入其中。

在代码中，声明一个名为 DV 。此数据表中没有行，因此 foreach 将永远不会执行其内部代码块。我想你可能想要遍历除DV以外的DataTable对象。还有另一个你应该使用的吗？

Step through your logic. If you want to iterate through the rows of a datatable, then you need to put rows into it before you try to loop through the rows.
In your code, you declare a new instance of DataTable called DV. There are no rows in this datatable so your foreach will never execute its internal code block. I''m thinking that you may have wanted to loop through a DataTable object other than DV. Is there another one that you should be using?

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