Question

我正在使用以下代码读取Excel并将其存储在数据集中。

     public DataSet ReadExcelDataToDataSet(Stream fileStream)
            {
                DataTable dataInExcelSheet = new DataTable();
                IExcelDataReader excelReader = ExcelReaderFactory.CreateReader(fileStream);
                DataSet excelDataSet = excelReader.AsDataSet(new ExcelDataSetConfiguration()
                {
                    UseColumnDataType = false
//Do we have any property here to convert all rows values to string datatype.
                });
                excelReader.Close();
                return excelDataSet;
            }

是否可以将Excel Sheet的所有值转换为字符串并将其作为字符串值存储在数据集中。

示例：

在Excel文件中，对于少数几列，我具有Int32和Double数据类型的值1,22.0。我想将这些值转换为字符串，然后将它们作为字符串存储在数据集中。

Answer 1

使用UseColumnDataType = false时，ExcelDataReader返回单元格为System.Object。

如果您需要退回System.String，则需要克隆DataSet结构，并在使用时将每个DataColumn的类型设置为System.String，然后使用DataTable.ImportRow()为您完成所有向System.String的转换。如果您需要进一步控制格式设置（例如，转换日期类型），也可以显式进行转换。

这是给你的例子...

// NuGet reference: ExcelDataReader v3.6.0 built from https://github.com/ExcelDataReader/ExcelDataReader/ExcelDataReader
// NuGet reference: ExcelDataReader.DataSet v3.6.0 built from https://github.com/ExcelDataReader/ExcelDataReader/ExcelDataReader.DataSet
using ExcelDataReader;
using System;
using System.Data;
using System.IO;
using System.Linq;

namespace Convert_IExcelDataReader_values_to_string
{
    class MainClass
    {
        public static DataSet ReadExcelDataToDataSet(Stream fileStream)
        {
            DataSet excelDataSet;
            using (IExcelDataReader reader = ExcelReaderFactory.CreateReader(fileStream))
            {
                var dataSetConfiguration = new ExcelDataSetConfiguration()
                {
                    UseColumnDataType = false
                };
                // This reads each Sheet into a DataTable and each column is of type System.Object
                excelDataSet = reader.AsDataSet(dataSetConfiguration);
            }

            var stringDataSet = ConvertToDataSetOfStrings(excelDataSet);
            return stringDataSet;
        }

        private static DataSet ConvertToDataSetOfStrings(DataSet sourceDataSet)
        {
            var result = new DataSet();
            result.Tables.AddRange(
                sourceDataSet.Tables.Cast<DataTable>().Select(srcDataTable =>
                {
                    var destDataTable = new DataTable(srcDataTable.TableName, srcDataTable.Namespace);
                    // Copy each source column as System.String...
                    destDataTable.Columns.AddRange(
                        srcDataTable.Columns.Cast<DataColumn>()
                            .Select(col => new DataColumn(col.ColumnName, typeof(String)))
                            .ToArray()
                            );
                    // Implicitly convert all source cells to System.String using DataTable.ImportRow()
                    srcDataTable.Rows.OfType<DataRow>()
                    .ToList()
                    .ForEach(row => destDataTable.ImportRow(row));
                    return destDataTable;
                })
                .ToArray()
                );
            return result;
        }

        public static void Main(string[] args)
        {
            using (var stream = File.Open("TestOpenXml.xlsx", FileMode.Open, FileAccess.Read, FileShare.Read))
            {
                var dataSet = ReadExcelDataToDataSet(stream);
            }
        }
    }
}

希望这会有所帮助！

Answer 2

使用扩展名的非LINQ版本添加到@AlwaysLearning答案。

public static class DataSetExtensions
{
    public static DataSet ToAllStringFields(this DataSet ds)
    {
        // Clone function -> does not copy the data, but just the structure.
        var newDs = ds.Clone();
        foreach (DataTable table in newDs.Tables)
        {
            // if the column is not string type -> set as string.
            foreach (DataColumn col in table.Columns)
            {
                if (col.DataType != typeof(string))
                    col.DataType = typeof(string);
            }
        }

        // imports all rows.
        foreach (DataTable table in ds.Tables)
        {
            var targetTable = newDs.Tables[table.TableName];
            foreach (DataRow row in table.Rows)
            {
                targetTable.ImportRow(row);
            }
        }

        return newDs;
    }
}

用法：

public DataSet ReadExcelDataToDataSet(Stream fileStream)
{
    DataTable dataInExcelSheet = new DataTable();
    IExcelDataReader excelReader = ExcelReaderFactory.CreateReader(fileStream);
    DataSet excelDataSet = excelReader.AsDataSet(new ExcelDataSetConfiguration()
    {
        UseColumnDataType = false
    }).ToAllStringFields();
    excelReader.Close();
    return excelDataSet;
}

如何将IExcelDataReader值转换为字符串数据类型

2 个答案: