vb.net - 當試圖從sql數據庫中選擇數據時，combobox顯示System.Data.DataRowView當試圖從sql數據庫中選擇數據時

Question

當我試圖從sql數據庫中選擇數據時，我得到了System.Data.DataRowView。這些是我的代碼：

...... 
myCommand = New SqlCommand("SELECT FirstName +' '+ LastName FROM tblVisitor", myConnection) 
myAdapter = New SqlDataAdapter(myCommand) 
myAdapter.Fill(myDataSet, "tblVisitor") 
cboName.DataSource = myDataSet.Tables(0) 
cboName.DisplayMember = "FirstName" 
cboName.DisplayMember = "LastName" 
cboName.ValueMember = "FirstName" 
cboName.ValueMember = "LastName" 
.............. 

我得到了上述錯誤。請幫忙。

Answer 1

您的SelectCommand既不返回列LastName也不返回FirstName。您只返回一列（兩列的串聯）。

所以這應該工作：

myCommand = New SqlCommand("SELECT VisitorID, LastName, FirstName, (FirstName +' '+ LastName)As FullName FROM tblVisitor", myConnection) 
myAdapter = New SqlDataAdapter(myCommand) 
myAdapter.Fill(myDataSet, "tblVisitor") 
cboName.DataSource = myDataSet.Tables(0) 
cboName.DisplayMember = "FullName" 
cboName.ValueMember = "VisitorID" 'change to the correct pk-column' 

Answer 2

您需要設置ValueMember以及DisplayMember。