C#的DataTable操作方法

蔚落 2022-06-18 08:36 288阅读 0赞

1.将泛型集合类转换成DataTable（表中无数据时使用）：

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public static DataTable NullListToDataTable(IList list)
            {
                var result = new DataTable();
                if (list.Count <= 0) return result;
                var propertys = list[0].GetType().GetProperties();
                foreach (var pi in propertys)
                {
                    if (pi != null)
                    {
                        result.Columns.Add(pi.Name, pi.PropertyType);
                    }
                }
                for (var i = 0; i < list.Count; i++)
                {
                    var tempList = new ArrayList();
                    foreach (var pi in propertys)
                    {
                        var obj = pi.GetValue(list[i], null);
                        tempList.Add(obj);
                    }
                    var array = tempList.ToArray();
                    result.LoadDataRow(array, true);
                }
                return result;
            }

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2.将泛型集合类转换成DataTable（表中有数据时使用）：

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public static DataTable NoNullListToDataTable<T>(IList<T> list)
            {
                var ds = new DataSet();
                var dt = new DataTable(typeof(T).Name);
                var myPropertyInfo =
                    typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
                foreach (var t in list)
                {
                    if (t == null) continue;
                    var row = dt.NewRow();
                    for (int i = 0, j = myPropertyInfo.Length; i < j; i++)
                    {
                        var pi = myPropertyInfo[i];
                        var name = pi.Name;
                        if (dt.Columns[name] != null) continue;
                        DataColumn column;
                        if (pi.PropertyType.UnderlyingSystemType.ToString() == "System.Nullable`1[System.Int32]")
                        {
                            column = new DataColumn(name, typeof(int));
                            dt.Columns.Add(column);
                            if (pi.GetValue(t, null) != null)
                                row[name] = pi.GetValue(t, null);
                            else
                                row[name] = DBNull.Value;
                        }
                        else
                        {
                            column = new DataColumn(name, pi.PropertyType);
                            dt.Columns.Add(column);
                            row[name] = pi.GetValue(t, null);
                        }
                    }
                    dt.Rows.Add(row);
                }
                ds.Tables.Add(dt);
                return ds.Tables[0];
            }

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3.表中有数据或无数据时使用,可排除DATASET不支持System.Nullable错误：

![复制代码][copycode.gif]

public static DataTable ToDataTable<T>(IList<T> list)
            {
                if (list == null || list.Count <= 0)
                {
                    var result = new DataTable();
                    object temp;
                    if (list == null || list.Count <= 0) return result;
                    var propertys = list[0].GetType().GetProperties();
                    foreach (var pi in propertys)
                    {
                        {
                            result.Columns.Add(pi.Name, pi.PropertyType);
                        }
                    }
                    for (var i = 0; i < list.Count; i++)
                    {
                        var tempList = new ArrayList();
                        foreach (var pi in propertys)
                        {
                            var obj = pi.GetValue(list[i], null);
                            tempList.Add(obj);
                        }
                        var array = tempList.ToArray();
                        result.LoadDataRow(array, true);
                    }
                    return result;
                }
                var ds = new DataSet();
                var dt = new DataTable(typeof(T).Name);
                var myPropertyInfo =
                    typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
                foreach (var t in list)
                {
                    if (t == null) continue;
                    var row = dt.NewRow();
                    for (int i = 0, j = myPropertyInfo.Length; i < j; i++)
                    {
                        var pi = myPropertyInfo[i];
                        var name = pi.Name;
                        if (dt.Columns[name] != null) continue;
                        DataColumn column;
                        if (pi.PropertyType.UnderlyingSystemType.ToString() == "System.Nullable`1[System.Int32]")
                        {
                            column = new DataColumn(name, typeof(int));
                            dt.Columns.Add(column);
                            if (pi.GetValue(t, null) != null)
                                row[name] = pi.GetValue(t, null);
                            else
                                row[name] = DBNull.Value;
                        }
                        else
                        {
                            column = new DataColumn(name, pi.PropertyType);
                            dt.Columns.Add(column);
                            row[name] = pi.GetValue(t, null);
                        }
                    }
                    dt.Rows.Add(row);
                }
                ds.Tables.Add(dt);
                return ds.Tables[0];
            }

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4.合并相同的DataTable：

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public static DataTable MergeSameDatatable(DataTable dataTable1, DataTable dataTable2)
            {
                var newDataTable = dataTable1.Clone();
                var obj = new object[newDataTable.Columns.Count];
                for (var i = 0; i < dataTable1.Rows.Count; i++)
                {
                    dataTable1.Rows[i].ItemArray.CopyTo(obj, 0);
                    newDataTable.Rows.Add(obj);
                }
                for (var i = 0; i < dataTable2.Rows.Count; i++)
                {
                    dataTable2.Rows[i].ItemArray.CopyTo(obj, 0);
                    newDataTable.Rows.Add(obj);
                }
                return new DataTable();
            }

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5.将两个列不同的DataTable合并成一个新的DataTable ：

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public static DataTable UniteDataTable(DataTable dt1, DataTable dt2, string dtName)
            {
                var dt3 = dt1.Clone();
                for (var i = 0; i < dt2.Columns.Count; i++)
                {
                    dt3.Columns.Add(dt2.Columns[i].ColumnName);
                }
                var obj = new object[dt3.Columns.Count];
    
                for (int i = 0; i < dt1.Rows.Count; i++)
                {
                    dt1.Rows[i].ItemArray.CopyTo(obj, 0);
                    dt3.Rows.Add(obj);
                }
    
                if (dt1.Rows.Count >= dt2.Rows.Count)
                {
                    for (var i = 0; i < dt2.Rows.Count; i++)
                    {
                        for (var j = 0; j < dt2.Columns.Count; j++)
                        {
                            dt3.Rows[i][j + dt1.Columns.Count] = dt2.Rows[i][j].ToString();
                        }
                    }
                }
                else
                {
                    for (var i = 0; i < dt2.Rows.Count - dt1.Rows.Count; i++)
                    {
                        var dr3 = dt3.NewRow();
                        dt3.Rows.Add(dr3);
                    }
                    for (var i = 0; i < dt2.Rows.Count; i++)
                    {
                        for (var j = 0; j < dt2.Columns.Count; j++)
                        {
                            dt3.Rows[i][j + dt1.Columns.Count] = dt2.Rows[i][j].ToString();
                        }
                    }
                }
                dt3.TableName = dtName;
                return dt3;
            }

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6.Datatable 转 List<Dictionary<string, object>：

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public static List<Dictionary<string, object>> DataTableToListDictory(DataTable table)
            {
                var ld = new List<Dictionary<string, object>>();
                for (var i = 0; i < table.Rows.Count; i++)
                {
                    var dic = new Dictionary<string, object>();
                    for (var j = 0; j < table.Columns.Count; j++)
                    {
                        dic.Add(table.Columns[j].ColumnName, table.Rows[i][j]);
                    }
                    ld.Add(dic);
                }
                return ld;
            }

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[copycode.gif]: /images/20220618/0a0a677e1f32487486939c8be6320637.png