打印数据表的内容

目前我有一段代码，它通过SQL连接查找数据库表，并将前五行插入Datatable(table(中。

using(SqlCommand _cmd = new SqlCommand(queryStatement, _con))
{
    DataTable Table = new DataTable("TestTable");
    SqlDataAdapter _dap = new SqlDataAdapter(_cmd);
    _con.Open();
    _dap.Fill(Table);
    _con.Close();
}

然后如何将此表的内容打印到控制台以供用户查看？

仔细研究后，我是否应该将内容绑定到列表视图，或者是否有直接打印它们的方法？现阶段我不关心设计，只关心数据。

任何指点都会很棒，谢谢！

您可以尝试以下代码：

foreach(DataRow dataRow in Table.Rows)
{
    foreach(var item in dataRow.ItemArray)
    {
        Console.WriteLine(item);
    }
}

更新1

DataTable Table = new DataTable("TestTable");
using(SqlCommand _cmd = new SqlCommand(queryStatement, _con))
{
    SqlDataAdapter _dap = new SqlDataAdapter(_cmd);
    _con.Open();
    _dap.Fill(Table);
    _con.Close();
}
Console.WriteLine(Table.Rows.Count);
foreach(DataRow dataRow in Table.Rows)
{
    foreach(var item in dataRow.ItemArray)
    {
        Console.WriteLine(item);
    }
}

下面是另一个将表转储为逗号分隔字符串的解决方案：

using System.Data;
public static string DumpDataTable(DataTable table)
        {
            string data = string.Empty;
            StringBuilder sb = new StringBuilder();
            if (null != table && null != table.Rows)
            {
                foreach (DataRow dataRow in table.Rows)
                {
                    foreach (var item in dataRow.ItemArray)
                    {
                        sb.Append(item);
                        sb.Append(',');
                    }
                    sb.AppendLine();
                }
                data = sb.ToString();
            }
            return data;
        }

正确的表格显示

static void print_results(DataTable data)
    {
        Console.WriteLine();
        Dictionary<string, int> colWidths = new Dictionary<string, int>();
        foreach (DataColumn col in data.Columns)
        {
            Console.Write(col.ColumnName);
            var maxLabelSize = data.Rows.OfType<DataRow>()
                    .Select(m => (m.Field<object>(col.ColumnName)?.ToString() ?? "").Length)
                    .OrderByDescending(m => m).FirstOrDefault();
            colWidths.Add(col.ColumnName, maxLabelSize);
            for (int i = 0; i < maxLabelSize - col.ColumnName.Length + 10; i++) Console.Write(" ");
        }
        Console.WriteLine();
        foreach (DataRow dataRow in data.Rows)
        {
            for (int j = 0; j < dataRow.ItemArray.Length; j++)
            {
                Console.Write(dataRow.ItemArray[j]);
                for (int i = 0; i < colWidths[data.Columns[j].ColumnName] - dataRow.ItemArray[j].ToString().Length + 10; i++) Console.Write(" ");
            }
            Console.WriteLine();
        }
    }

foreach (DataRow dr in myDataTable.Rows)
{
    foreach (var item in dr.ItemArray)
    {
        Console.Write(item + " ");
    }
    Console.WriteLine();
}

¹以前的答案与此类似，但没有清晰地格式化行条目和单元格

之间的分隔

使用以下扩展方法(C#9.0(：

/// <summary>
/// Provides extension methods for the <see cref="DataTable"/> type.
/// </summary>
public static class DataTableExtensions
{
    /// <summary>
    /// Generates a textual representation of the data of <paramref name="table"/>.
    /// </summary>
    /// <param name="table">The table to print.</param>
    /// <returns>A textual representation of the data of <paramref name="table"/>.</returns>
    public static String Print(this DataTable table)
    {
        String GetCellValueAsString(DataRow row, DataColumn column)
        {
            var cellValue = row[column];
            var cellValueAsString = cellValue is null or DBNull ? "{{null}}" : cellValue.ToString();
            return cellValueAsString;
        }
        var columnWidths = new Dictionary<DataColumn, Int32>();
        foreach (DataColumn column in table.Columns)
        {
            columnWidths.Add(column, column.ColumnName.Length);
        }
        foreach (DataRow row in table.Rows)
        {
            foreach (DataColumn column in table.Columns)
            {
                columnWidths[column] = Math.Max(columnWidths[column], GetCellValueAsString(row, column).Length);
            }
        }
        var resultBuilder = new StringBuilder();
        resultBuilder.Append("| ");
        foreach (DataColumn column in table.Columns)
        {
            resultBuilder.Append(column.ColumnName.PadRight(columnWidths[column]));
            resultBuilder.Append(" | ");
        }
        resultBuilder.AppendLine();
        foreach (DataRow row in table.Rows)
        {
            resultBuilder.Append("| ");
            foreach (DataColumn column in table.Columns)
            {
                resultBuilder.Append(GetCellValueAsString(row, column).PadRight(columnWidths[column]));
                resultBuilder.Append(" | ");
            }
            resultBuilder.AppendLine();
        }
        return resultBuilder.ToString();
    }
}

这是由包含单个表的数据表完成的

        SqlConnection con = new SqlConnection(constr);
        con.Open();
        SqlCommand cmd = new SqlCommand("select * from info", con);
        SqlDataAdapter ad = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        ad.Fill(dt);
        Console.WriteLine(dt.Columns[0].ColumnName.ToString());
        Console.WriteLine(dt.Rows[1].ItemArray[0].ToString());

这是由保存表集合的数据集完成的

        SqlConnection con = new SqlConnection(constr);
        con.Open();
        SqlCommand cmd = new SqlCommand("select * from info", con);
        SqlDataAdapter ad = new SqlDataAdapter(cmd);
        DataSet dt = new DataSet();
        ad.Fill(dt);
        Console.WriteLine(dt.Tables[0].Columns[0].ColumnName.ToString());
        Console.WriteLine(dt.Tables[0].Rows[0].ItemArray[0].ToString());

两者都会得到相同的结果。只有数据集包含表的索引编号。

用列打印数据表内容行

Here is solution 
DataTable datatableinfo= new DataTable();
// Fill data table 
//datatableinfo=fill by function or get data from database
//Print data table with rows and column

for (int j = 0; j < datatableinfo.Rows.Count; j++)
{
    for (int i = 0; i < datatableinfo.Columns.Count; i++)    
        {    
            Console.Write(datatableinfo.Columns[i].ColumnName + " ");    
            Console.WriteLine(datatableinfo.Rows[j].ItemArray[i]); 
        }
}

Ouput :
ColumnName - row Value
ColumnName - row Value
ColumnName - row Value
ColumnName - row Value

在这里的另一个答案的基础上，这里有一个方法可以将DataTable转换为CSV输出，并将列名添加为输出中的第一行：

public static string DataTableToCsv(DataTable table)
{
    string result = string.Empty;
    StringBuilder resultBuilder = new StringBuilder();
    if (table != null && table.Rows != null && table.Columns != null && table.Columns.Count > 0)
    {
        int lastItemIndex = table.Columns.Count - 1;
        int index = 0;
        foreach (DataColumn column in table.Columns)
        {
            resultBuilder.Append(column.ColumnName);
            if (index < lastItemIndex)       // if not the last element in the row
                resultBuilder.Append(", ");  // add the separator
            index++;
        }
        resultBuilder.AppendLine();  // add a CRLF after column names row
        foreach (DataRow dataRow in table.Rows)
        {
            lastItemIndex = dataRow.ItemArray.Length - 1;
            index = 0;
            foreach (object item in dataRow.ItemArray)
            {
                resultBuilder.Append(item);
                if (index < lastItemIndex)       // if not the last element in the row
                    resultBuilder.Append(", ");  // add the separator
                index++;
            }
            resultBuilder.AppendLine();  // add a CRLF after each data row
        }
        result = resultBuilder.ToString();
    }
    return result;
}

用法示例：

DataTable table = new DataTable();
....
Console.WriteLine(DataTableToCsv(table));

请注意，此方法无法正确处理(即转义(包含引号或逗号的数据。但是，作为一种快速而肮脏的方式，将数据表转储到控制台或其他任何地方进行查看就足够了。

使用以下扩展方法。

public static string ToCSV(this DataTable t, bool header)
{
    StringBuilder sb = new StringBuilder();
    int i = 0;
    int maxColIdx = 0;
    
    if (t?.Columns?.Count > 0)
    {
        maxColIdx = t.Columns.Count - 1;
        if (header)
        {
            foreach (DataColumn c in t.Columns)
            {
                sb.Append(c.ColumnName);
                if (i < maxColIdx) sb.Append(", ");
                i++;
            }
            sb.AppendLine();
        }
        if (t?.Rows?.Count > 0)
        {
            foreach (DataRow r in t.Rows)
            {
                i = 0;
                foreach (var item in r.ItemArray)
                {
                    sb.Append(item);
                    if( i < maxColIdx) sb.Append(',');
                    i++;
                }
                sb.AppendLine();
            }
        }
    }           
    return sb.ToString();
}

打印DataTable和DataRow的函数。

    private void printDataTable(DataTable Table)
    {
        foreach (DataRow dataRow in Table.Rows)
        {
            printDataRow(dataRow);
        }
    }
    private void printDataRow(DataRow drow)
    {
        StringBuilder sb = new StringBuilder();
        sb.AppendLine(string.Join(",", drow.ItemArray));
        Console.WriteLine(sb);
    }

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