c#添加问题？

[zhjdelphi]

MySqlDataAdapter = MyFunction.GetSqlDataAdapter("SELECT distinct college from college where college='" + comboBox1.Text.ToString().Trim() + "'");
MySqlDataAdapter.Fill(MyDataSet , "college");
if (MyDataSet.Tables["college"].Rows.Count > 0)
{
MessageBox.Show("同名学院已存在!", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}

我这个为什么只能添加一条再添加一条（不一样）也弹出同名学院已存在


明明学院aa
不存在我调试查了下

MyDataSet.Tables["college"].Rows.Count =1？
为什么啊 ？

[grearo]

MySqlDataAdapter = MyFunction.GetSqlDataAdapter("SELECT distinct college from college where college='" + comboBox1.Text.ToString().Trim() + "'");
MyDataSet.Clear();
MySqlDataAdapter.Fill(MyDataSet , "college");
if (MyDataSet.Tables["college"].Rows.Count > 0)
{
MessageBox.Show("同名学院已存在!", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}

[初吻给了烟]

因你的MyDataSet 不是局部变量，改成局部变量

[初吻给了烟]

MySqlDataAdapter.Fill(MyDataSet , "college"); 是往里面追加的，改成局部变量就可以了

[billclinton8]

MySqlDataAdapter = MyFunction.GetSqlDataAdapter("SELECT college from college where college='" + comboBox1.Text.ToString().Trim() + "'");
MyDataSet.Clear();
MySqlDataAdapter.Fill(MyDataSet , "college");
if (MyDataSet.Tables["college"].Rows.Count > 0)
{
MessageBox.Show("同名学院已存在!", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}

[huguang2yq]

MyDataSet.Tables["college"].Rows.Count > 0
这个判断.......如果行数大于0,就执行下面的..
你已经添加了一条,肯定不能再添加啦.....晕...

[cnjimbo]

MySqlDataAdapter = MyFunction.GetSqlDataAdapter("SELECT distinct college from college where college='" + comboBox1.Text.ToString().Trim() + "'");
MyDataSet = New DataSet();
MySqlDataAdapter.Fill(MyDataSet , "college");
if (MyDataSet.Tables["college"].Rows.Count > 0)
{
MessageBox.Show("同名学院已存在!", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}

[zhjdelphi]

晕，原来是这个问题啊
谢谢了