错误时从字符串

Question

转换日期和/或时间当我尝试运行此代码，我收到此错误：

conversion failed when converting date and/or time from character string 

我就在这行错误：

g_muallak_tarihi = DateTime.Parse(row_muallakt["Muallak_tarihi"].ToString()); 

要存储既是日期和时间也是仅日期的值，我使用DateTime数据类型。我不知道该怎么做。你有什么想法？

这是我的代码：

public void cs_hmuallak() 
{ 
    string cs_hmuallak = null; 
    SqlConnection cnn; 

    cs_hmuallak = @"Data Source= .\SQLEXPRESS; Initial Catalog=mydb;Integrated Security= True"; 

    cnn = new SqlConnection(cs_hmuallak); 

    try 
    { 
     cnn.Open(); 

     { 
       SqlDataAdapter da_muallakt = new SqlDataAdapter("SELECT M.Muallak_tutari FROM Muallak M INNER JOIN Hasar H ON M.Hasar_no= H.Hasar_no INNER JOIN Police P ON p.Police_no=h.Police_no where p.Acenta_kodu='"+cbx_acenta.Text+"' and p.Brans_kodu='"+cbx_brans.Text+"' and M.muallak_tarihi<=(Select M.muallak_tarihi from muallak M where M.muallak_tarihi=(select max(muallak_tarihi) from muallak where muallak_tarihi<=@parameter)) and M.Muallak_tarihi=(SELECT max(M.Muallak_tarihi) FROM Muallak M INNER JOIN Hasar H ON M.Hasar_no= H.Hasar_no INNER JOIN Police P ON p.Police_no=h.Police_no where p.Acenta_kodu='"+cbx_acenta.Text+"' and p.Brans_kodu='"+cbx_brans.Text+"' and M.muallak_tarihi<=(Select M.muallak_tarihi from muallak M where M.muallak_tarihi=(select max(muallak_tarihi) from muallak where muallak_tarihi<=@parameter))) ", cnn); 

       da_muallakt.SelectCommand.Parameters.AddWithValue("@parameter",g_listetarihi.ToString("yyyy-mm-dd")); 
       DataTable table_muallakt = new DataTable(); 
       da_muallakt.Fill(table_muallakt); 
       foreach (DataRow row_muallakt in table_muallakt.Rows) 
       { 
        if (row_muallakt["Muallak_tutari"] != DBNull.Value) 
        { 
         if (row_muallakt["Muallak_tarihi"] != DBNull.Value) 
         { 
          g_muallak_tarihi = DateTime.Parse(row_muallakt["Muallak_tarihi"].ToString()); 
          g_muallak_tutari = int.Parse(row_muallakt["Muallak_tutari"].ToString()); 
         } 
        } 
       }     
     } 
    } 
    catch (Exception ex) 
    { 
     MessageBox.Show(ex.ToString()); 
    } 
}  

Answer 1

假设Muallak_tarihi被定义为DATETIME柱（其是应就像它所持有的那样），所有这些工作都转化为从字符串是不需要的。

你可以简单地用数据读取器直接使用GetDateTime为了得到它，或者简单地把价值：

g_muallak_tarihi = row_muallakt["Muallak_tarihi"] as DateTime; 

此外，您所使用的参数（@parameter）应也是DATETIME - 直接通过，而不是使用ToString：

da_muallakt.SelectCommand.Parameters.AddWithValue("@parameter",g_listetarihi); 

Answer 2

使用的String.format

da_muallakt.SelectCommand.Parameters.AddWithValue("@parameter", string.Format("{0:yyyy-MM-dd}",g_listetarihi.ToString()); 

MSDN日期时间的格式：http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx