C# asp.net 错误：无法将类型“对象”隐式转换为“字符串”。存在显式转换（您是否缺少演员表？）
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asp.net error: Cannot implicitly convert type 'object' to 'string'. An explicit conversion exists (are you missing a cast?)
提问by user2721914
I want to retrieve data from a table in sql server called hotel using select WHERE statement and I get the above error. Can anyone help?
我想使用 select WHERE 语句从 sql server 中名为 hotel 的表中检索数据，但出现上述错误。任何人都可以帮忙吗？
SqlConnection cnn = new
SqlConnection(ConfigurationManager.ConnectionStrings["myConnectionString"].ToString());
cnn.Open();
SqlCommand cmd = new SqlCommand();
cmd.CommandText = "SELECT RoomsAvailable FROM Hotel WHERE HotelName = '" +
this.DropDownList1.Text + "'";
cmd.Connection = cnn;
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = cmd;
DataSet ds = new DataSet();
da.Fill(ds, "Hotel");
SqlCommandBuilder cb = new SqlCommandBuilder(da);
DataRow dsRow = null;
foreach (DataRow dsRow_loopVariable in ds.Tables["Hotel"].Rows)
{
dsRow = dsRow_loopVariable;
//This line is where the error comes in.
this.txtHotel.Text = (dsRow["RoomsAvailable"]);
}
回答by Habib
Change
改变
this.txtHotel.Text = (dsRow["RoomsAvailable"]);
To
到
this.txtHotel.Text = (dsRow["RoomsAvailable"].ToString());
回答by Allan Elder
Or change to
或更改为
this.txtHotel.Text = dsRow["RoomsAvailable"] as string;
and you won't get an exception if the value is null.
如果值为空，您将不会收到异常。
回答by sk2185
Try this Code
试试这个代码
this.txtHotel.Text = Convert.ToString (dsRow["RoomsAvailable"]);
回答by Paddyd
回答by Suraj Singh
Well i saw this code
好吧，我看到了这段代码
cmd.CommandText = "SELECT RoomsAvailable FROM Hotel WHERE HotelName = '" +
this.DropDownList1.Text + "'";
and this.DropDownList1.Textwill fetch you selected value not text .
just have you given HotelNamesas dropdownvalues ?
并且this.DropDownList1.Text将获取你选择的值不是文本。你只是给出HotelNames了dropdown值吗？
and for error Try
和错误尝试
Convert.ToString(dsRow ["RoomsAvailable"]);
