Question

我有一个返回额外列的存储过程。我无法控制存储过程。我想使用以下表单生成我的工作表：

ws.Cells.LoadFromDataTable(dt, true, OfficeOpenXml.Table.TableStyles.Light8)

如何输出我想要的列？

我试图弄清楚Linq查询，但问题是列名不可访问，所以我无法指定我想要的列。

        SqlConnection cx = new SqlConnection(util.GetConnectionString());
        SqlCommand cmd = new SqlCommand("StoredRept", cx);
        cmd.CommandType =  CommandType.StoredProcedure;
        SqlDataAdapter ta = new SqlDataAdapter();
        ta.SelectCommand = cmd;
        DataTable dt = new DataTable();
        ta.Fill(dt);


        FileInfo newFile = new FileInfo("c:\temp");
        ExcelPackage epp = new ExcelPackage(newFile);
        var ws = epp.Workbook.Worksheets.Add("WS");

        // here is where I would like to copy certain columns off into another data table but I haven't been able to figure out how  

        ws.Cells.LoadFromDataTable(dt, true, OfficeOpenXml.Table.TableStyles.Light8);

非常感谢任何帮助。

Answer 1

如果从表中删除某些列是唯一的问题，那么很容易解决。尝试这样的事情：

// array of parents
const p = [
  {
    name: 'SBRF IANUA EFS CC Integration',
    expand: false,
    check: 'N',
    jsonDiffPath: '/repo/Dynamics/Business Service/SBRF IANUA EFS CC Integration',
    changeCount: 1,
    items: [
      {
        name: 'CRP-37920',
        expand: false,
        check: 'N',
        jsonDiffPath: null,
        changeCount: 1,
        items: [],
        op: 'MODIFY',
        oldSnapshot: '723012',
        newSnapshot: '948053',
        myChange: false
      }
    ],
    id: 'F5ZGK4DPF5CHS3TBNVUWG4ZPIJ2XG2LOMVZXGICTMVZHM2LDMUXVGQSSIYQESQKOKVASARKGKMQEGQZAJFXHIZLHOJQXI2LPNY======',
    objectId: '30263',
    group: 'repo',
    category: 'Dynamics',
    type: 'Business Service'
  }
];

// define a function that describes how a child should merge with its parent
function merge(p) {
  // p is the parent object
  // c are all of p's children defined in items
  const child = p['items'];
  // on the item that we return we only want keys that appear in the parent
  // create an array for the flattened results
  const f = [];
  child.forEach(el => {
    let keys = Object.keys(p);
    // clone the parent object
    let c = Object.assign({}, p);
    // basically unset the items since we are already iterating of them
    child['items'] = [];
    // now iterate over all of the childrens attrs described by the parents parameters
    keys.forEach(k => {
      // the childs value for each key
      const val = el[k];
      if (val !== undefined && val !== null) {
        // handle your special cases in here, such as the name
        if (k === 'name') {
          c['name'] = '[' + el['name'] + '] ' + c['name'];
        } else {
          // default behavior for the non specific cases
          c[k] = el[k]
        }
      }
    });
    // add the object to the array of flattened children
    f.push(c);
  });
  return f;
}

// iterate over all of the parents and their children
// to do this we want to apply a map to all of the parents
const m = p.map(el => merge(el));

您可以使用以下方法按名称查找列并将其删除：

var dt = new DataTable();
dt.Columns.Add("First", typeof(string));
dt.Columns.Add("Second", typeof(string));
dt.Columns.Add("Third", typeof(string));
dt.Columns.Add("Fourth", typeof(string));
dt.Columns.Add("Fifth", typeof(string));

for (var i = 1; i < 6; i++)
{
    dt.Rows.Add($"First {i}", $"Second {i}", $"Third {i}",$"Fourth {i}",$"Fifth {i}");
}

//dt.Dump();//If you have linqpad this is handy to dump table to output

//REMOVE THE COLUMNS. 
dt.Columns.RemoveAt(1);
dt.Columns.RemoveAt(2); 

//dt.Dump();//again in linqpad this dumps table with remaining 3 columns

这是获取所需列的列表的linq查询。

var col=dt.Columns["Second"];
dt.Columns.Remove(col);

请注意如何使用列索引或名称从行对象中获取值。

Answer 2

您可以使用ScrollViewer代替IEnumerable<T>加载电子表格吗？如果是这样的话：

DataTable

如果您需要var someColumns = dt .AsEnumerable() .Select(row => new { When = row.Field<DateTime>("When"), What = row.Field<string>("What"), HowMany = row.Field<int>("ColumnNameInDatabase"), });，可以通过this或this等任何方法将DataTable转换为{。}}。

BUT

坦率地说，我回答了你的问题，但IMO你手头有一个更大的问题，那就是使用那些过时的IEnumerable对象而不是DataTable。例如，如果您考虑使用IEnumerable<T>库，则可以执行此操作：

Dapper

我看到您正在使用util.GetConnectionString() .Query("StoredRept", commandType: CommandType.StoredProcedure) // Extension method from Dapper .Select(dyn => new { When = (DateTime)dyn.When, What = (string)dyn.What, HowMany = (int)dyn.ColumnNameInDatabase })库进行Excel操作。它可以加载EPPlus个数据，但不限于IEnumerable<T>。

指定哪些列位于数据表中

2 个答案:

BUT