c# - 比较数据集中的单元格和前置信息

Question

好吧，我对我的 C# 有点生疏，所以这可能很容易，但我只是没有得到，但它晚了，我的大脑受伤了。我正在尝试获取数据集中的每个值，如果它们短于给定长度，则在开头添加零。问题是我不知道如何着手实现它的概念。任何帮助表示赞赏。这是我到目前为止所拥有的。

        //Connection and location to Excel file
        OleDbConnection conn = new OleDbConnection();
        conn.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source= C:\\Users\\User\\Desktop\\New folder\\DHS_Weekly.xlsx; Extended Properties= \"Excel 12.0;HDR=No;IMEX=1;ImportMixedTypes=Text;\"";

        //Select location in the file
        OleDbCommand command = new OleDbCommand
            (
                "SELECT * FROM [WEEKLY.COOLING.PAYMENT$C:D]", conn
            );
        //Create a dataset to temp store the information
        DataSet dsDHS = new DataSet();
        OleDbDataAdapter adapter = new OleDbDataAdapter(command);
        adapter.Fill(dsDHS);


        //Having the data Grid display the results of the data set DHS(dsDHS)
        dataGridView1.DataSource = dsDHS.Tables[0];

         //New string that sets the path to the output of a text file 
        //The dataset will be output to this text file
        string path = @"C:\\Users\\User\\Desktop\\New folder\\DHStest.txt";

        //New streamwriter and stringbuilder that uses the path created above
       StreamWriter textOut = new StreamWriter(new FileStream(path, FileMode.Create, FileAccess.Write));
       StringBuilder str = new StringBuilder();

       //uses strings to correctly display the dataset 
       //removes the last 3 rows from output (2 Null rows and last line not needed)
       //removes the first row by starting at 1 instead of zero. (first row is null)
       for (int i = 1; i <= dsDHS.Tables[0].Rows.Count - 3; i++)
       {
           for (int j = 0; j <= dsDHS.Tables[0].Columns.Count - 1; j++)
           {
               str.Append(dsDHS.Tables[0].Rows[i][j].ToString());
           }
           //Adds a new line between each row
           str.AppendLine();
       }
        //writes the output,  this is just so I can check things before finalizing
       textOut.Write(str.ToString());
       textOut.Close();

    }
}

Answer 1

假设我正确理解您的要求，并且您希望最终长度为 6 个字符:

for (int j = 0; j <= dsDHS.Tables[0].Columns.Count - 1; j++)
{
    var originalValue = dsDHS.Tables[0].Rows[i][j].ToString();
    var padded = originalValue.PadLeft(6, '0');

    str.Append(padded);
}

将“6”更改为所需的最终宽度。