我需要通过读取现有数据表的第一行中的数据来向现有数据表添加列。然后需要从文本文件向新列添加数据。例如,请将下面给出的表视为现有数据表。我在这里提到了第一行的值(dm1,dm2,..)
以下提供的是我需要的数据表。 dm4行数据和dm6行数据已添加到此处的两个新列
有人可以帮我确定一个解决方案。提前致谢
private DataTable CreateDT1(string name, ListBox list)
{
DataTable dt = new DataTable();
//there are many files in the list box
string[] files = new string[list.Items.Count];
for (int x = 0; x < list.Items.Count; x++)
{
object s = list.Items[x];
files[x] = s.ToString();
}
int lineno = 0;
//for each file in list box
for (int i = 0; i < files.Length; i++)
{
int count = 0;
string file = files[i];
using (System.IO.StreamReader sr = new System.IO.StreamReader(file))
{
string line;
while ((line = sr.ReadLine()) != null)
{
if (line.Contains(name))//filtering the line which contains a specific string"
{
if (i == 0)
{
if (lineno == 0)//first choosen line of the first text file.
{
//splitting the choosen line
string[] split = line.Split(',');
int result = split.Length;
dt.Rows.Add();
//Based on the number of split length of this row i have added columns
for (int x = 0; x < result; x++)
{
DataColumn dc = new DataColumn(x.ToString(), Type.GetType("System.String"));
dt.Columns.Add(dc);
dt.Rows[lineno][x+1] = split[x];
}
}
else//splitting and adding other lines of the first text file
{
string[] split = line.Split(',');
int result = split.Length;
dt.Rows.Add();
for (int x = 0; x < result; x++)
{
dt.Rows[lineno][x + 1] = split[x];
}
}
}
else//adding lines of other text files underneath the same columns
{
if (count != 0)
{
string[] split = line.Split(',');
int result = split.Length;
if (result+1 <= dt.Columns.Count)
{
dt.Rows.Add();
for (int x = 0; x < result; x++)
{
dt.Rows[lineno][x + 1] = split[x];
}
}
else//My issue occurs here when there are additional columns in the other files. Basically when the split length of a line is higher than the previous text files. Then i have to add a new column at the specific positions
{
dt.Rows.Add();
for (int x = 0; x < result; x++)
{
if (split[x]!=dt.Rows[0][x+1])
{
DataColumn dc = new DataColumn(split[x], Type.GetType("System.String"));
dt.Columns.Add(dc);
dt.Rows[lineno][x + 1] = split[x];
}
}
}
}
else
{
lineno -= 1;
count += 1;
}
}
lineno += 1;
}
}
}
}
return dt;
}
答案 0 :(得分:-1)
如果将SQL查询更改为 SELECT dm1,dm2,dm3,NULL AS dm4,dm5,NULL as dm6,dm7 你会得到一些你可以立即使用的填空值