如何从数据库获取数据,然后将其转换为整数数据类型 [英] How do I get the data from database and then convert it into integer datatype
问题描述
我在从数据库获取数据并将其转换为整数数据类型时遇到问题
我尝试过:
string constr =provider = microsoft.jet.oledb.4.0; data source = | datadirectory | Flight.mdb;
OleDbConnection con = new OleDbConnection(constr);
con.Open();
string sql =从AllFlights中选择Economy,其中Flight_name ='+ TextBox6.Text +';
OleDbCommand cmd = new OleDbCommand(sql,con);
OleDbDataAdapter da = new OleDbDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
GridView1.DataSource = ds;
GridView1.DataBind();
Int32 anInteger;
anInteger = Convert.ToInt32(sql);
anInteger = Int32.Parse (sql);
它给了呃ror输入字符串的格式不正确。
首先,根据 Convert.ToInt32 Method(String)(System) [ ^ ]和
Int32.Parse方法(字符串)(系统) [ ^ ]
两者都转换指定的数字的字符串表示形式为等效的32位有符号整数。这里的关键词是数字的字符串表示,因此罪魁祸首是sql
变量。调查一下。
或者,使用 Int32。 TryParse方法(String,Int32)(系统) [ ^ ]。
其次,你应该使用参数化SQL [ ^ ]以防止sql注入。
为了实现可持续的自助未来,您应该学习如何如何在Visual C#中跟踪和调试 [ ^ ]
i have a problem in getting the data from database and convert it into integer datatype
What I have tried:
string constr = "provider= microsoft.jet.oledb.4.0;data source=|datadirectory|Flight.mdb";
OleDbConnection con = new OleDbConnection(constr);
con.Open();
string sql = "select Economy from AllFlights where Flight_name='"+TextBox6.Text+"' ";
OleDbCommand cmd = new OleDbCommand(sql, con);
OleDbDataAdapter da = new OleDbDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
GridView1.DataSource = ds;
GridView1.DataBind();
Int32 anInteger;
anInteger = Convert.ToInt32(sql);
anInteger = Int32.Parse(sql);
it is giving the error "Input string was not in a correct format."
Firstly, according to Convert.ToInt32 Method (String) (System)[^] and
Int32.Parse Method (String) (System)[^]
Both convert the specified string representation of a number to an equivalent 32-bit signed integer. The key word here is "string representation of a number", so the culprit is thatsql
variable. Look into it.
Alternatively, use Int32.TryParse Method (String, Int32) (System)[^].
Secondly, you should use parameterized SQL[^] to prevent sql injection.
For a sustainable self-help future, you should learn how to How to trace and debug in Visual C#[^]
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