无法从“string”转换为“System.Data.DataColumn[]

[userpengcl]

protected void Button1_Click(object sender, EventArgs e)
{
DataTable dsIIS = new DataTable();
DataTable dsSwt = new DataTable();
dsIIS = it.IISMatch();
dsSwt = vt.SwtMatch();

DataTable dsIISSwt = new DataTable();

dsIISSwt = Join(dsIIS, dsSwt,"id","visistorId");


}
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public DataTable Join(DataTable First, DataTable Second, DataColumn[] FJC, DataColumn[] SJC)
{

//创建一个新的DataTable

DataTable table = new DataTable("Join");


// Use a DataSet to leverage DataRelation

using (DataSet ds = new DataSet())
{

//把DataTable Copy到DataSet中

ds.Tables.AddRange(new DataTable[] { First.Copy(), Second.Copy() });

DataColumn[] parentcolumns = new DataColumn[FJC.Length];

for (int i = 0; i < parentcolumns.Length; i++)
{

parentcolumns[i] = ds.Tables[0].Columns[FJC[i].ColumnName];

}

DataColumn[] childcolumns = new DataColumn[SJC.Length];

for (int i = 0; i < childcolumns.Length; i++)
{

childcolumns[i] = ds.Tables[1].Columns[SJC[i].ColumnName];

}


//创建关联

DataRelation r = new DataRelation(string.Empty, parentcolumns, childcolumns, false);

ds.Relations.Add(r);


//为关联表创建列

for (int i = 0; i < First.Columns.Count; i++)
{

table.Columns.Add(First.Columns[i].ColumnName, First.Columns[i].DataType);

}

for (int i = 0; i < Second.Columns.Count; i++)
{

//看看有没有重复的列，如果有在第二个DataTable的Column的列明后加_Second

if (!table.Columns.Contains(Second.Columns[i].ColumnName))

table.Columns.Add(Second.Columns[i].ColumnName, Second.Columns[i].DataType);

else

table.Columns.Add(Second.Columns[i].ColumnName + "_Second", Second.Columns[i].DataType);

}


table.BeginLoadData();

foreach (DataRow firstrow in ds.Tables[0].Rows)
{

//得到行的数据

DataRow[] childrows = firstrow.GetChildRows(r);

if (childrows != null && childrows.Length > 0)
{

object[] parentarray = firstrow.ItemArray;

foreach (DataRow secondrow in childrows)
{

object[] secondarray = secondrow.ItemArray;

object[] joinarray = new object[parentarray.Length + secondarray.Length];

Array.Copy(parentarray, 0, joinarray, 0, parentarray.Length);

Array.Copy(secondarray, 0, joinarray, parentarray.Length, secondarray.Length);

table.LoadDataRow(joinarray, true);

}

}

}

table.EndLoadData();

}


return table;

}
这是代码，我想要实现的是两个DataTable的联合查询，但是怎么调用啊，我新手，很多不懂！

[userpengcl]

谁能帮帮我啊，谢谢了！

[bdmh]

Join后两个参数是column数组，不是字符串，你要创建两个column数组，里面应该存放的是要合并一起显示的列
比如

DataColumn[] cols1= new DataColumn[]{dsIIS.Columns[0],dsIIS.Columns[1]};
DataColumn[] cols2= new DataColumn[]{dsSwt.Columns[0],dsSwt.Columns[1]};

dsIISSwt = Join(dsIIS, dsSwt,cols1,cols2);

[userpengcl]

bdmh
DataColumn[] cols1= new DataColumn[]{dsIIS.Columns[0],dsIIS.Columns[1]};
这里后面的大括号里面是什么意思啊？

[kaikai_kk]

定义数组并赋初值,即像这样:

DataColumn[] cols1= new DataColumn[2];
cols1[0] = dsIIS.Columns[0];
cols1[1] = dsIIS.Columns[1];

[userpengcl]

DataRelation r = new DataRelation(string.Empty, parentcolumns, childcolumns, false);
这里出错，说父列和子列不具有类型匹配的列