sqlserver合并DataTable并排除重复数据的通用方法分享

///summary>
/// 将两个列不同的DataTable合并成一个新的DataTable
////summary>
///param name="dt1">源表/param>
///param name="dt2">需要合并的表/param>
///param name="primaryKey">需要排重列表（为空不排重）/param>
///param name="maxRows">合并后Table的最大行数/param>
///returns>合并后的datatable/returns>
public static DataTable MergeDataTable(DataTable dt1, DataTable dt2, string primaryKey, int maxRows)
{
//判断是否需要合并
if (dt1 == null dt2 == null)
{
return null;
}
if (dt1 == null dt2 != null)
{
return dt2.Copy();
}
else if (dt1 != null dt2 == null)
{
return dt1.Copy();
}
//复制dt1的数据
DataTable dt = dt1.Copy();
//补充dt2的结构（dt1中没有的列）到dt中
for (int i = 0; i dt2.Columns.Count; i++)
{
string cName = dt2.Columns[i].ColumnName;
if (!dt.Columns.Contains(cName))
{
dt.Columns.Add(new DataColumn(cName));
}
}
//复制dt2的数据
if (dt2.Rows.Count > 0)
{
Type t = dt2.Rows[0][primaryKey].GetType();
bool isNeedFilter = string.IsNullOrEmpty(primaryKey) ? false : true;
bool isNeedQuotes = t.Name == "String" ? true : false;
int mergeTableNum = dt.Rows.Count;
for (int i = 0; i dt2.Rows.Count mergeTableNum maxRows; i++)
{
bool isNeedAdd = true;
//如果需要排重时，判断是否需要添加当前行
if (isNeedFilter)
{
string primaryValue = dt2.Rows[i][primaryKey].ToString();
string fileter = primaryKey + "=" + primaryValue;
if(isNeedQuotes)
{
fileter = primaryKey + "='" + primaryValue + "'";
}
DataRow[] drs = dt.Select(fileter);
if (drs != null drs.Length > 0)
{
isNeedAdd = false;
}
}
//添加数据
if (isNeedAdd)
{
DataRow dr = dt.NewRow();
for (int j = 0; j dt.Columns.Count; j++)
{
string cName = dt.Columns[j].ColumnName;
if (dt2.Columns.Contains(cName))
{
//防止因同一字段不同类型赋值出错
if (dt2.Rows[i][cName] != null dt2.Rows[i][cName] != DBNull.Value dt2.Rows[i][cName].ToString() != "")
{
dr[cName] = dt2.Rows[i][cName];
}
}
}
dt.Rows.Add(dr);
mergeTableNum++;
}
}
}
return dt;
}